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Full text of "The geology of the Waihi-Tairua subdivision, Hauraki division"

..SD Boundary 



\-WeiMeMa River 
"Waiwaif^a River 



Vaiwawa fiver 



i 



%. 



•^ 



Digitized by the Internet Archive 
in 2013 



http://archive.org/details/geologyofwaihitaOObell 



Ih accornpany BuUntinN" 15 .Waiht-Tairuay Suidjvisijon.Hau^aklDivisiorv. AuxMand Land, BisUtct . 




Section along Line AB. Whitian^a Survey District 




Section along Line CD, Tairua Survey District 




XiOTM.—A great fault marking the 
eastern limits of a *'grabe?i" may 
exist in this vicinity. 



Section along Line EF, Ohinemuri &Waihi North Survey Districts. 



Natural Scale 



— Reference to Geolo g ical Colours 




IGNEOUS. 



fTerlkry rolcanle nck$ of lh» " First Period." 

(UPPER EOCENE .' Rhjolites Aoidio. 

TO MIOCENE) j Anijesitlc and daoltio tuffe, breooias, ag- ) 
glomerates, and lava-flows. Semlbaelc. j 



Compiled and drawn hy G.EJUirris, Feb. 19t2 



Tertliry rolcanic rooks of the " Second 

Period. ' (Beesofi'a Island Series.) 
I " A," Older. 

jAndesltlo and dacitic tuffs, breccias, ag- 
(MIOCENE P) ■{ \ {lomerates. and lava-flows. Semlbasie. 

j "B," Younger 

. Andesltic and dacitio tuffs, breccias, ag- 

[ glomerates, and lava-flows. Semlbaelc. 



(Tertiary volcanic rocks of the " Ttiird Period." 
fthyolltio and dacltic tuffs, breccias, ag-1 
glomerates, and lava-flows. Acidic.) 



JAMES MACKINTOSH BELL 
DIRECTOR 



SEDIMEZN-TARY. 

iUnoon&olidsted or poorly -consolidated debris. 
(PRE-PLEISTOCENEj River-terraces. river-flatB, sea-beachesj 
AND RECENT) j drifting sands, talus slopes, narbourJ 
muds, awamp- deposits. 



Z] 



Bf/ Auth*rHy : John Maohay. 6overnmtnt Printer 



700-8./e.2S7. 



TABLE OP GEOLOGICAL FORMATIONS COMPARED WITH THOSE OF PREVIOUS WRITERS. 



COX, 1882. 


PARK, 1897. 


MACLAREN, 1900. 
(Eefers to Coromandel mining centre only.) 


McKAY, 1905. 


C'lassification in Coromandel B) lletin. 
(Eraser and Adams. 1907.) 


Classification in Thames Bulletin. 
(Eraser, 1910.) 


Classification in Waihi-Tairua Bulletin. 
(Bell and Eraser, 1911.) 




Palaeozoic (Probably Devonian)* — 
Slaty .shale.s and grauwackes 
(gold-bearing). 


Carboniferous (M.-utai Slatb.s 
of Hochstettee)— 
Slaty shales, grauwackes. sand- 
.stones, crushed breccias, fel- 
sites, and felsitic tuffs. 


Te Anatj Series (Upper Devonian) — 
Stratified beds of igneous material with 
associated eruptive and dyke rocks. 


1 

< 

li 

P-l 


Tokatea Hill Series — 

Argillites and grauwackes, with in- 
terstratified beds of ignenus ma- 
terials. 


Tokatea Hill Series (Pre-Jurassic)— 
Argillites and grauwackes, with inter- 
stratified beds of igneous material. 






Maitai Series (Lower Carboniferous) — 
Sandstones, slaty shales, and mudstones, 
with intruded dyke rocks. 




Lower Cabbonifbeotjs and Upper 
Devonian — 
Slates, sandstones, and felsites. 


Moehau Series — 
I, Argillites and grauwackes. 






Wairoa Series (Triassio) — 

Sandstones and conglomerates formed of 
igneous rocks, and slates and mudstones. 


Manaia Hill Series (Jurassic)^ 

Argillites, grauwackes. grits, and fine 
conglomerates. 


Manaia Hill Series (Jurassic)— 

Ai'gillites, grauwackes. grits, and fine 
conglomerates. 


^ [These series do not occur in the Waihi- 
Tairua Subdivision.] 




Lower Eocene — 

Marine limestone, marly sand- 
stones, and conglomerates with 
brown coal. 


Lower Eocene — 

Clay marls, slate conglomer- 
ates, foraminiferal limestones, 
with small coal-seams. 


S5 
H 
O 
O 

1 

O 

IS 

o 
o 

1 

« 


'Lower or Coal-beaeing Series — 
Conglomerates, sandstones, and 
shales with coal. 


ToREHiNE Series (Lower Eocene) (?) — 
(a.) Conglomerates, sandstones, and 

shales with coal-seams. 
(6.) Marly sandstones, calcareous sand- 
stones, limestone. 


[The Torehuie Series does not occur in 
Thames Subdivision.] 




Crbtaobo-Tertiary— 

Coal-bearing series of Cabbage Bay. 


Middle and LTpper Beds — 

Marly greensands with concretions, 
compact limestones and calca- 
reous sandstones. 


- 


Age doubtful — 

Auriferou.s rocks of the Thames. 


Upper Eocene — 

Andesitic lavas, tuff.s, and ag- 
glomerates (gold-bearing). 


Upper Eocene or Oligocene — 
A n tl e s i t e s (augite and horn- 
blende), fresh and decomposed, 
fine-grained tuffs. 


Tii/Umes-Tokatea Group— (Eocene) (?)— 

Eruptive matter, mostly andesitic flow 

rocks, and breccias, &c., cut by dykes. 


Tertiary Y o l c a n i c Rocks oi- 
THE " EIR.ST Period " (Upper 
Eocene) (?)— 

Acidic : Rhyolitic tuffs. 

Semi-basic : Andesitic and dacitic tuffs, 
breccias, and lava-flows. 


T K R T I a R Y V L C A N I C RoCKS OF 

THE " First Period " (Upper 
Eocene) (?)— 
Andesitic and dacitic tuffs, breccias, 
agglomerates, and lava-flows. 


1' E r t I A R Y Volcanic Rocks of the 
" First Period " (Upper Eocene 
OR Miocene) (?)— 


Breccias and tuffs. 


Kapanga Group (Upper Eocene)— 
Same as above. 


Andesitic, dacitic, and rhyolitic tuffs 
breccias, and lava-flows. 


Lower Miocene — 
Trachytic breccias. 


Miocene— 

Andesitic breccia.s and tuffs. 


Miocene — 

Trachytic and audesitic agglo- 
merates, breccias, and dykes. 


Beeson's Island Group (Miocene) — 
Eruptive matter wholly andesitic or da- 
citic ; .stratified tuff beds with coal. 


Tertiary Volcanic Rocks of the 
" Second Period " or Beeson's 
Island Series (Miocene) — 
Semi-basic : Andesitic and dacitic tuffs, 
breccias, and lava-flows. 


Tertiary V^olcanic Rof:KS of the 
" Second Period " or Beeson's 
Island Series (Miocene) — 
Andesitic and dacitic tuffs, breccias, 
agglomerates, and lava-flows. 


Tertiary Volcanic Rocks of the 
" Second Period " or Beeson's 
Island Series (Miocene) — 
(a.) Older: Andesitic and dacitic tuffs, 
breccias, and lava-flows. 
Younger : Andesitic and dacitic 
tuffs, breccias, and lava-flows. 




Pliocene — 

Rhyolitic lavas and tuffs. 


[The Pliocene acidic rocks do 
not occur in the area mapped by 
this writer.] 

Plei.stocbne — 

Rivor-terraees, lacustrine beds. 


o 

a 

CM 


(a.) Older Rhyolites — 
(6.) PuMicEous Agglomerate or 
Whitianga Beds — 
Breccia agglomerates mostly of acid 
rocks, pumioeous sands, &c., with 
beds of lignite. 


Tertiary Volcanic Rocks of the 
" Third Period " (Pliocene)— 
Acidic : Rhyolitic tuffs, breccias, lava- 
flows. 


Tertiary Volcanic Rocks of the 
" Third Period " (Pliocene) — 
Rhyolitic tuffs, breccias, agglomerates, 
lava-flows. 


Tertiary' Volcanic Rocks of the 


Pliocene — 
Rhyolite formation. 


(f.) Middle Rhyolites — 

Massive flow and intrusive roclvs, for 
most part resting on (6). 


" Third Period " (Pliocene)— 
Rhyolitic and dacitic tuffs, breccias, ag- 
glomerates, and lava-flows. 




{d.) Y'"ouNOEB Rhyolites— 

Brecciated or pitchstone rhyolites 
chiefly developed in the upper 
basin of the Ohinemuri watershe<l. 






Pleistocene — 

High-level gravel terraces. 


Raised Beaches (Post-Pliocene) — 
Coarse beach-gravels, chiefly along the 
west side of the peninsula. 


Pre ■ Pleistocene, Pleistocene, and 
Recent— 
Unconsolidated or poorly consolidated 
debris. River - terraces, river - beds, 
sea-beaches, drifting sands, talus 
slopes. 


Pleistocene and Recent — 

Unconsolidated or poorly consolidated 
debris. River - terraces, river - flats, 
ch'ifting sands, talus slopes, harbour 
muds, and swamp deposits. 


Pleistocene and Recent — 

River-flats, river-terraces, swamp da- 
posits, harbour muds, sea-beaches, 
drifting sands, and talus deposits. 




Recent — 

River-flats, swamps, and blown 
sands. 


Recent — 

Alluvial flats, harbour-muds, 
swamp-deposits. 


Alluvial (Post-Pliocene) — 

Coarse gravel, river-deposits, and finer 
sediments. 








Intru.sions of Younger Pliocene 
Age — 
Table Mountain, &c. 


Intrusive Igneous Rocks of Various 

Periods— 
Acidic : RhyoUte. 
Semi-basic : Diorite, porphjrite, ande- 

site, dacite. 


Intrusive Igneous Rocks of Various 
Periods — 
Diorite, porph,\Tite, andesite, dacite. 
rhyolite. 


Intrusive Igneous Rocks of Various 
Periods (Post-Pliocenb and Older)— 
Andesite, dacite, and rhyolite. 



' lu Trans. N.Z. Inst., vol. xxxvi, 1903, page 413. Prof. Park remarks: 
grauwackes which form the floor of the Hauraki Peninsula." 
Geo. Bull. No. 15. 



• Rocks belonging to the .Jurassic systbui, in association with those of the Trias, form the greater portion of the Tararua, Ruahine, and Kaimanawa Mountains in the North Island; and we have no reason to assume a greater age for the slaty shales, sandstones, and 



lb aoioinpanf Bxjleiinlf 15, Waihi-Tairna. Siihclixi.iimv.Hataald BiyistaTV. AucklanjlZantJDi.striTf 




To (Mt:orri party Builettn ^'^ 15. Wai/u -Taiinw Szthd^'isimv , Hota-oki. Uivisivn . Auehlortd^ LoJid/ DisirU- 




, SvHetin2f« 15, Waihl-Tairua, SubcHt'isien.lIa'^akiDivMo'V. AiJ^Mcmd, Land, DistrUt. 




By Authority: Jof^n hiackay, Govtmwtni Printer. 



To >i^on,pa/vy BuU^'Jxn JV^ J5, WoLhi-Taijua. SuJidivLsimv . Hai^aJd.Divtsiorv. Au^JtJxifuI Lcu,^. Di^U Ut. 




Tn^onometricaL StaiLon. 
Edges of Bush 

WaterRacee 

Shafts aiid Drives- .. 
Wn/erfaUs und Dams 

ConwihdanddrawTi by G EJIarru . Dec 131 f 



By Auihcrity: John Maekay, Govimmtnt Printer. 



lb ac^on^ariy BiiUeUnIf° 15. Whzhl-TcUruu Sxihdiviswrv.MatfJ'aktDivvsion'. AtuJd/infl Land, District. 




Compiled ajuiibratmfyG.EHcDTU Teb !V!2. 



Outcrops with observed strJhe and dip A 
Breccias V 

Quarti vfim K ><l SinUr.- [jlo] 



Th iiccorripojiy JiuZle/J.n TV" /5 , Woihl-Tairiui, Sulidiyistoth . HaitraJtLDlvisiorv, AxAA^hLarui. Lcui^ Di^itrixit. 




- Reference 

SDods shown thtLB .—t^"^ 

Tracks ^^ ^^ _ .„..= 

Trigonometrical StaUons „ „- C ©iB^i' 

Ed^esofBush „ _ _ „ _-*<8?-3tf^*.* 

S^arnp „--„- *^k%* 

WlUxrRcLC^B „ ., _ „— !!i«^ 

Trajn. Liixea „ „ _ i ■-■ 

Shafts ojut Drives „ „ _ a / 

WfO'.r/alL. and Dams _ „ „ „ _ ^'■^-^- 



TOPOGRAPHICAL MAP OF ^^ 



\mmm syiw 



lasTiiSi 



CarnpiZed. /r a m , data, obtamedf frmTt, 
the LoTids and, Surrey DepartTnent, 
and, <Ldd:UtonaZ, suryeys by KM.Qrahjurv. \^ 



- Scale of Chain s ~ 



M M M RT 



Compiled and drawn, by G.RHoMi.Hec. iW - 



By Authority: John Mackay, Govtmmtrtt pri 



lb accompany MuUelui lf° 75. Wothi-Tairua SuidJyiswn.HaiaaJdlliyision,, AuxMarul Laiul District, 





Frontispiece.^ 



NEW ZEAT. AND 



J^eparttnent O 




of "24Ttn«?&. 



geolooicaij sijuvey branch 

(P. G. MORGAN, Director.) 



BULLETIN No. 15 (New Series). 



THE GEOLOGY 






OF THE 



WAIHI-TAmCA SUBDIVISION, 



HAURAKI DIVISION. 



JAMES MACKINTOSH BELL AND COLIN FRASER. 



ISSUED UNDER THE AUTHORITY OP THE HON. THE MINISTER OF MINKS. 




WELLINGTON. 
BY AUTHORITY : JOHN MACKAY, GOVERNMENT PRINTER. 

1912. 



PREFA(]E 



Some delay in the issue of this hiillctiii has been unavoidable ovviu^^ 
to the removal of Dr. Bell and Mr. Fraser to England. The authors have 
not had an opportunity of revising the proofs, and it is possible that 
some small errors or inconsistencies have thus escaped notice. 

The issue of this bulletin completes the geological survey of the 
mining districts to the north of the Ohinemuri Hiver. During the last 
season Dr. J. Henderson and Mr. J. A. Bartrum have been engaged on 
the area to the south and south-east of the Tairua-Waihi Subdivision, 
so that, with the exception of Te Puke, all the mining districts in tlie 
Hauraki Division have now been examined. 



Wellington, 28th May, 1912. 



P. G. MORGAN, 
Director, Geological Survey. 



LETTER OF TRANSMITTAL. 



621 Salisbury House, London B.C , 

29th September, 1911. 
Sir, — 

I have the honour to transmit, through Mr. Percy Gates 
Morgan, luj successor as Director of the New Zealand Geological Survey, 
a report on the geology of the Waihi-Tairua Subdivision, Hauraki, 
Auckland. 

This report is the result of field examinations carried out prior to 
March, 1911, by Mr. Colin Fraser and myself, then Mining Geologist and 
Director of the Survey respectively. 

The report has mainly been compiled subsequent to the date of 
Mr. Eraser's and my own departure from New Zealand. 

1 have the honour to be, 
Sir, 
Your obedient servant, 

J. M. BELL. 
Hon. Minister of Mines, Wellington. 



CONTENTS 



Preface . . 

Letter of Transmittal 



Page 
iii 
iv 



General Description of Area 
Salient Geological Features 
Acknowledgments 



Chapter I. — General Information. 
Pago 



Officers connected with the Field-work 
Literature 



Pass 
4 
4 



Chapter II. — History and Technology of Mining. 



History of Mining Development 
Mineral Production 



17 



Mining and Treatment of Ores 
Financial Conditions 



18 
24 



Introduction 
The Land 

(1.) Flats 

(2.) Plateaux .. 

(3.) Peaks and Ridges 



Chapter III. — Physiography. 

. . 27 J The Shore-line . . . . . . 30 

. . 28 Drainage-channels . . . . . . 32 

. . 28 Swamps . . . . . . . . 32 

. . 29 Springs . . . . . . . . 33 

29 Man's Influence on the Physical Features . . 34 



Chapter IV.— General Geology. 



Outline of the Main Geological Features 
Table of Formations 

Pre-Jurassic and Jurassic Stratified Rocks . . 
Igneous Rocks . . 

(1.) Tertiary Volcanic Rocks of the "First 
Period " 
General Statement 
Age .. 
Distribution 
Petrology 
(2.) Tertiary Volcanic Rocks of the " Second 
Period " (Beeson's Island Series). . 
General Statement 
Age and Correlation 

(a.) Older Group of Beeson's 
Island Series . . 
Dbtribution 
Structure and Petrology . . 



3.-) 


Igneous 


Rocks — continwd. 




37 


(2.) T 


iTtiary Volcanic Uocksof the '•Second 




38 




Period "' (Beeson's Island Series) — 
conlinued. 




39 




Age and Correlation — continued. 
(6.) Younger Group of Beeson's 




39 




Island Series . . 


45 


39 




Distribution 


45 


39 




Structure and Petrology . . 


45 


39 


(3.) Tertiary Volcanic Rocks of the "Third 




40 




Period " 


40 






General Statement 


4(i 


43 




Age 


4(i 


43 
43 




Distribution 


4(J 




Structure and Petrology . . 


47 


(4.) I 


ntrusive Rocks of Various Periods 


49 






General Statement 


49 


44 




Distribution and Petrology 


49 


44 


Pleistocene and Recent Deposits 


40 


44 


Regional Earth -movements and Faulting 


50 



Chapter V. — Mineral Veins, and CoNDmoNs in Mineralized .Vreas. 



Perio<ls of Mineralization . . 

The Vein Fissures 

The Mineralizing Agents . . 

Rock-alteration connected with Mineralization 

Mineralogy of the Vein-material 

Non-metallic Minerals . . 

Metallic Minerals 
Types of Mineral Deposits and Structure of 

the Vein -material 
Sinter-deposits . . 



52 


Oxidation 


62 


52 
53 


The Ore-deposits 

(a.) Major Structural Features .. 


62 
63 


54 


(6.) The Nature of the Rock enclosing the 




56 


Veins . . 


63 


56 


(c. ) Minor Structural Features 


64 


58 

60 
61 


(d.) Depth 
Underground Temperatures 
Underground Gases 
Underground Water 


64 
66 
67 
67 



VI 



■ i'ii'st Pfiiod " Volcank-s) 
("Second Period" Vol- 



Chaptkr VI. — Detailed Descriptions of Mining Areas and Mining Claims. 



Waihi Goldfield . . 
Introduction . . 
Topography 
Geology 

(«.) Dacites (' 
(6.) Andesites 

canics 
(c.) Rhyolites ("Thii-d Period") Aol- 

canics 
{(l.) Andesitio Rocko of Doubtful Age . . 
Detailed Structure 
Vein-system 

Origin of the Vein Fissures 
Sequence of Mineral Deposition in the \'eiiis 
Nature of the Vein-material 
The Ore-shoots 
Waihi Mine 
Equipment . . 
Martha Section 
Development 
Geological Structure 
Veins and Ore-deposits 
Martha Lode 
Branches of Martha 
Empire Lode 
Royal Lode 
Edward Lode 
Union-Silverton Section 
Union Lode 
Amaranth Lode 
Silverton Lode 
Mascotte Lode 
Statistics, Exploratory Work proceeding 
and proposed, &c. 
Ore-reserve 
Output 
Exploration 
Waihi Grand Junction Aline 
Equipment . . 

Grand Junction Eastern Section 
Underground Development . . 
Geological Structure 
Veins 

Martha Lode 
No. 2 Lode 
Mary Lode 
Grace Lode 
Empire Lode 
Royal Lode 
George Lode 
Other Veins 
Western Section 
Statistics, Exploration proceeding and 
proposed, &c. 
Ore-reserve 
Output 
Exploration 
Waihi Extended Claim 
Geological Structure 
Veins 
Pride of Waihi Claim 
Waihi Reefs Consolidated Claim 
Other Claims . . 

Waihi Romulus Claims 
Waihi Gladstone Claim 







Page 


The Vicinity of Gumtown 


. 72 


Kapowai Claim 


. 72 


Welcome Jack Claim 


. 74 


Big Beetle Claim 


. 74 


Golden Reefs Claim 


. 75 


Boat Harbour and Vicinity 


. 75 


Boat Harbour . . 


. 75 


Neave's Bay . . 


. 75 


Te Karo 


. 75 


Stony Creek 


. 76 


Lower Tairua 


. 76 


Tairua Broken Hills Claim 


. 77 


Tairua Golden Hills Claim 


. 81 


Tairua Monarch ConsoUdated Claim 


. 82 


Other Claims . . 


. 83 


Neavesville Area . . 


. 83 


Golden Belt Claim 


. 84 


Champion Claim 


. 86 


Ready Bullion Claims . . 


. 87 


Chelmsford Claim 


. 87 


" Fourth Branch " of Tairua River 


. 88 


Tairua Valley above " Fourth Branch " 


. 88 


Ohui . . 


. 88 


Phoenix Claim 




. 89 


Dreadnought Claim 




. 91 


Great Mexican Claim 




. 91 


Wharekawa Valley 




. 92 


Luck-at-Last Claim 




. 92 


Goldwin Claim 




. 93 


Whangamata 




. 95 


Auckland Claim 




.. 95 


Glamorgan Claim 




. 96 


Wharekirauponga 




. 97 


Puriri Valley 




. 98 


Omahu Valley . . 




. 98 


Sheet Anchor Claim 




. 99 


We Three Claim 




. 99 


Klondike Claim 




. 100 


Maratoto Valley 




. 100 


Walker's Maratoto 




. 100 


Maratoto Consolidated . . 




. 101 


Silverstream Plain 




. 102 


Tellurides Proprietary Claims 




. 103 


Peel's Creek Prospects . . 




. 104 


Waitekauri Extended Claim 




. 104 


Komata District.. 




. 105 


Komata Reefs Mine 




. 105 


Waitekauri Valley 




. 108 


Golden Cross Claim 




. 108 


Grace Darling Claim 




. Ill 


Durbar Claim . . 




. 112 


Huanui Claim 




. 113 


Old Waitekauri Claim . . 




. 113 


Scotia Claim . . 




. 114 


JubUee Claim . . 




. 115 


MaorUand Claim 




. 116 


Owharoa 




. 117 


Rising Sun 




. 118 


Mackaytown 




. 119 


Ascot Cinnabar Mine 




. 119 


Waihi Beach 




. 121 


Waihi Beach Claims 




. 122 



Page. 
123 
123 
123 

123 
124 

125 

125 
125 
126 
128 
129 
132 
134 
140 
143 
143 
145 
145 
145 
145 
147 
150 
150 
151 
152 
158 
159 
160 
160 
160 

160 
160 
161 
161 
161 
162 
162 
162 
163 
164 
164 
164 
165 
165 
165 
166 
167 
167 
168 

168 
168 
168 
168 
169 
169 
170 
171 
171 
171 
171 
172 



Chapter VII. — Summary of the Mineral Rksoubces of the Waihi-Tairua Subdivision. 



(a.) The Present Position and Future Pro- 
spects of Gold-Silver Mining . . . . 173 

(b.) Mineral Deposits other than Gold-Silver 

Veins . . . . . . 180 

Mercury . . . . . . . . 180 



(6.) Mineral Deposits, &c. — continued. 

Selenium . . . . . . . . 181 

Coal .. .. ..181 

(c.) Stones for Building and Macadamizing . . 181 



Vll 



LIST OF ILLUSTRATIONS. 



Plate 


I 


Plate 


II 


Plate 


III 


Plate 


IV 


Plate 


\ 


Plate 


VI 


Plate 


VII 


Plate 


VIII 


Plate 


IX 


Plate 


X. 



Facing page 
Panoramic View of Waihi . . . . . . . . . . Frontispiece. 

Waihi (Jold-raining Company's Main Pumping-station at No. 5 Shaft . . 18 

Waihi (irand Junction Company's Mill . . . . 21 

Waihi (!old-mining C<)m])any's Mill, Waikino . . . . 22 

Valley of Tairiia River, looking toward <iorge . . . . . . . . 27 

View looking North-east above Junction of Hikutaia and Waipahcke Streams, Rhj-olito 

Pinnacle, Maratoto . . . . . . . . . . . . . . 29 

Otahu Inlet — Mouth of Wharekirauponga Stream — on Eastern Coast-line, with Mayor 

Island in the Distance . . . . . . . . . . . . . . 31 

Waterfalls in Hihi Creek, a Tributary of the Kauaeranga . . . . 32 

Opencut, Martha Hill, Waihi Mine, looking West . . . . 34 

Rhyolite, showing markctl Columnar Structure. From Upper (iorge of Kauaeranga 

River . . . . 47 



LIST OF DIAGRAMS. 

Page 

Showing DLstribution of Sedimentary Rocks in the Hauraki Peninsula . . . . . . 35 

Diagrammatic Sketch, showint; tho I)i.'<positii>n of the Ore-shoots in the Kapowai Mine 73 
Plan showing the various \'eins and Productive Zones '" Ore back to bsu'k," in tho Tairua Broken 

Hills Claim (Tairua) .. .. .. .. .. .. .. .. 70 

Diagrammatic Section, showing Geological Structure in Maoriland Claim, Waitokauri lit; 

Fig. 1. Diagrammatic Section of the Siliceous Sinter-complex (Mackaytown) .. .. 120 

Fig. 2. Showing Modes in which tho Cinnalxir occurs in the Siliceous Sinter (Mackaytown) . . 120 
Plan showing approximately the Relationship of Vein -Assuring to Rock-structure in the VVaihi and 

Waihi (Jrand .Junction Mines at the l.tXK) ft. Ix>vcl (Xo. 9 Waihi, No. ."> .Junction) . . 131 
Sketch-plan of a very common Disposition of the \'einstone in both the Waihi and the Waihi fJrand 

Junction Ixodes at the Deeper Horizons 13;{ 

Cross-section on Martha Lode, Waihi Mine . . . . 148 
Vertical Cross -sect ion, showing Geological Structure and Principal Veins of the Martha System 

(VVaihi Mine) . . . . 149 



LIST OF MAPS AND SECTIONS. 



New Zealand, showing Land Districts and Divisions 

Hauraki Division, showing Survey Districts and Area geologically 8urveye<l 

Map of the Lower Tairua Mining Area 

Map of the Ohui Mining Area 

Map of the Maratoto Mining Area 

Golden Cross Claim, Waitekauri. Plans and Sections No. 1 Reef at different Levels 

Plan of No. 4 Level, Waihi Mine 

Plan showing Geological Formation, Veins, Faults, and Principal Workings at the deepest 

existing Levels, VVaihi Goldfield 
Cross-section on Lines K-K", K^-K 3, K3-K< .. 
Vertical L<jngitudinal Section on Lines A-B, A'B'C'.A^B'C^ 
Topographical Map of Whitianga Survey District 
Topographical Map of Tairua Survey District 

Topographical Map of Ohinemuri and Waihi North Survey Districts 
Geological Map of Whitianga Survey District 
Geological Map of Tairua Survey District 

Geological Map of Ohinemuri and Waihi North Survey Districts 

Geological Sections across Whitianga, Tairua, Ohinemuri, and Waihi North Survey Districts 
Map of the Principal Portion of the VVaihi (Joldfield, showing Surface Geology, General Position 

of the Reefs in the Older Dacites, Mining Claims, Shafts, Boreholes, &c. 



Facing page 
viii 
viii 

88 

92 
104 
112 
128 

128 

168 

172 

In portfolio. 




By Authority : John Mackay, Gcvemwi4nt PrirUtr. 



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FITZ«0Y fTRYPHENA 



JAMES MACKINTOSH SEU 



COLVILLE, 



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MAP OF 

HAURAKI DIVISION 

SHOWING SURVEY DISTRICTS 

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TOC^e i2.32S . 



BULLETIN No. 15 (NEW SERIES). 

THE GEOLOGY 

OF THE 

WAIHI-TAIRUA SUBDIVISION, 

HAURAKI, AUCKLAND. 



CHAPTER I. 



GENERAL INFORMATION. 



Page. Page. 

General Description of Area . . 1 Officers connected with the Field-work . . 4 

Salient Geological Features . . 3 Literature . . . . . . 4 

Acknowledgments . . 4 

General De-scriptiox ok .A.rea. 

The Waihi-Tairua Sul)di vision, in the Hauraki Peninsula, comprises the four survey districts 
Whitianga, Tairua, Ohinemuri, and Waihi North, and covers an area of 142'9 square miles. 
It is bounded on the north by the Coromandel Subdivision, on the west by the Thames Sub- 
division, on the .south by the Aroha Subdivision, and on the east by the open Pacific 
Ocean. 

The northern and central parts of the area are drained chiefly by the various streams 
entering the upper part of Whitiaiiga Estuary, and by the Tairua, ^^^)ar('kawa. and Otahii 
streams. All of these streams flow to the eastern seaboard. To the south, the country is 
drained by the Ohinemuri to the Thames River, and thence to the Hauraki Gulf. The 
Thames River also receives the waters of the Kauaeranga. Puriri, Omahu. Hikutaia. Komata, 
and smaller streams, all of which flow from the elevated country constituting the western 
portion of the subdivision. 

Except for the alluvial flats occurring in the lower courses of the principal streams, and 
the Waihi Plain, which is mainly of volcanic origin, the area is everywhere hilly, and may 
even be designated mountainous. The highest point is Mount Kaitaraldhi, which reaches 
an altitude of 2,740 ft. 

Almost all the land-surface of the Waihi-Tairua Subdivision was originally covered 
with a dense and luxuriant forest. Now, however, large portions of this primeval vegeta- 
tion have been destroyed by repeated fires, and have been replaced by stimted growths of 
1 — Waihi-Taiiua. 



fern and manuka. This change is, of coiirso, especially apparent in the vicinity of the mining 
settlements and on the low-lying arable lands. Again, wherever kauri-lumbering has been 
condvuited, bracken-clad spurs bristling with blackened tree-trunks testify to the ravages 
of fires following lumbering operations. Every year the fern on much of this open country 
is burned off. in order to facilitate the search for the fossil kauri -gum. The fires thus lighted 
spread into the green bush, destroying in places valuable standing timber. 

The kauri is much the most valuable tree growing in the subdivision, both for genera 
construction -work and for mine-timbers. Most of the kauri forest has already been cut, 
and that which remains in accessible localities is rapidly being removed. Other than kauri, 
there is no tree which is here regarded as of much importance in the timber trade, though 
rimu is being sawn in a few localities. Mixed bush is, however, being cut for mine-timbers 
and for fuel near Waihi and elsewhere. 

Among the most common forest trees in the area may be mentioned puriri {Vitex liicens), 
pohutukawa (Metrosideros tomentosa), rata {Metrosideros rnbnsta), tawa (Beilschmiedin tnwa), 
and tararaire (B. tarariri). The nikau palm {Rhopalostylis sapida) and various species of 
tree-fern, together with abundant creepers, give in places a subtropical aspect to the lower 
slopes of the valleys. 

As may be supposed from the existence of so luxuriant a vegetation, the cUmate is every- 
where mild, equable, and humid. The rainfall throughout the subdi^^sion is considerable, 
although the available figures submitted later refer only to Wailii Town, which is one of the 
wettest places in the area. The eastern seaboard in general is favoured with a sminier 
climate than the wooded, hilly, or mountainous interior. On the actual seashore frosts 
rarely occur. In winter, away from the coast occasional frosts are experienced, but 
snow never falls except on the higher hills, and there hes only for brief periods. At 
Waihi Town meteorological records show that the mean annual temperature over a 
period of seven years amoimted to 56° Fahr. The thermometer (standard exposure) 
ranged from 85-8° Fahr. in summer to 21° Fahr. in winter. The average rainfall for the 
last eleven years amounted to 83-5 in., and for the last four years (1907, 1908, 1909, and 
1910) to 102-03 in. per annum. Rain fell on 228 days during 1907, which was the 
wettest year on record ; and for 220 days in 1906, which was the driest of the last five 
years. Rainfalls of 4 in. or 5 in. in twenty-four hours are not infrequent. During th^ 
great storm of the 29th March, 1910, no less than 12-15 in. of rain fell in twelve hours 
and a half, and the Ohinemuri River rose 15 ft. in one night. 

As the population of the subdi\nsion at present depends for its existence mainly 
upon mining, the principal settlements are found in the \'icinity of the working-mines 
and prospects. Some farming is being carried on in the lower reaches of the larger 
streams, such as the Tairua, Whenuakaite. Waiwawa, Hikutaia, and Ohinemuri, and to 
a limited extent elsewhere. Nomad bands of Maoris, Croatians, and occasionally other 
nationalities, eke out an existence in the northern and central parts of the subdivision by 
digging for kauri-gum. Lumbering is still conducted in the area, but year by year to 
a diminisliing extent. Fishing in a small way is carried on at the Maori settlement of 
Homunga, and elsewhere on the sea-coast east of Waihi. 

Owing to the fact that the boundaries of the census district do not correspond with 
those of the subdi^'ision it is impossible to state exactly the number of inhabitants in the 
latter. However, the total European popvdation does not greatly exceed ten thousand. 
In addition, there are about four or five hundred Maoris — a number more or less con- 
stantly changing with the migrations of these people to other districts. By far the 
greater part of the population is within Waihi Borough, which, according to the census 
of 1911, contains some 6,436 persons. Waikino is the next largest settlement entirely 
within the subdivision. The townships of Paeroa and Karangahake are situated on the 
eastern and southern boimdaries, respectively, of the area under review. Maratoto 



Valley, Komata Valley, the lower parts of Ohinemuri and Tairiia valleys, and the settle- 
ment of Gumtowii carry the remainder of the white population. Most of the Maoris 
live in scattered pas near the inlets of Wharekawa and ^Vlm^gamata. 

The means of communication within the subdi\nsion compare favourablv with those 
obtaining in any other goldfield of similar age and importance. Almost everyAvhere, 
owing to the generally hilly nature of the coimtry, road-making is difficult and expensive. 
Waihi is connected by a branch railroad with Paeroa, a river-port on the main Thames- 
Auckland line. This branch railroad also passes through Waikino, Owharoa, and 
Karangahake. The numerous roads giving access to the various settlements in the 
valleys on the eastern and western sides of the main water-parting are shown on the 
maps accompanpng this report. Three well-graded cross-country tracks exist — namely, the 
Puriri-Tairua Track, the Omahu-Whangamata Track, and the Hikutaia-Wliangamata Track. 
These tracks connect settlements situated on the railway-line, which traverses the plains of 
the lower Thames Valley, with the settlements on the eastern side of the main range. 

Ill general, the scenery in the interior may be described as wild rather than beautiful. 
In places the scarred rhyolitic peaks, rising above a luxuriant though sombre growth, give 
a rugged grandeur. Elsewhere feni-covered slopes, with backgrounds of densely forested 
hills, present an extensive but distinctly monotonous landscape. Along the sea-coast the 
scenic effects are more pleasing. Here precipitous chffs, presenting a bold front to the 
Pacific, alternate with sandy bays, which are generally bordered by stately pohutukawa trees. 
Off the coast rock-girt islands of bizarre shape form in places a ])icturesc]ue foreground. 

.S.VI.IKNT OEOLOOir.AL FeATIKKS. 

The geology of the NVaihi-Tairua Subdi%nsion affords ample scope for the petrologist 
and the student of general vulcanology. while the ore-occurrences present many problems 
of economic importance. 

The consolidated rocks of the subdivision are entirely of igneous origin, and belong 
mostly to three periods of volcanic activity. To the north-west of the subdivision an 
irregularly denuded floor of Jurassic and pre-Jurassic sedimentary rocks appears, but in 
the area under review these sedimentaries are deeply depressed, and are unlikely to be 
penetrated even in deep mine-workings. The oldest volcanics consist of andesitic and 
dacitic lavas and breccias. These are followed by a second series, differing but shghtly 
in petrological character from the first. In this second series, however, fragmental 
rocks are more conspicuous and the lavas in general more glassy. The youngest series 
of volcanics is mostly rhyoUtic in character. The rock-complex is intruded in various 
places by dykes of andesite and dacite. 

Each of the three series of volcanics has, throughout relatively extensive areas, been 
altered by hydrothermal action. Areas of important metallization are, however, comparatively 
few, and are apparently limited to the volcanics of the " First " and " Second " periods. 

Principal economic interest centres about the Waihi Gioldficld, the more productive 
portion of which appears to lie within a relatively large intrusion of dacite. At Komata, 
Waitekauri. Maratoto, and other minor camps gold-bearing (|uartz veins occur in andesites 
or dacites, while at Taiiua, Neavesville, Ohiii. and Wailii R<';icli the productive veins are 
in rhyohtes. 

The goldfields of the Waihi-Tairua Subdivision, in conuuon with those of the whole 
Hauraki area, exhibit many striking resemblances to the Washoe, Cripple Creek, Tonopah, 
De Lamar, and Gold Hill (Utah) mining districts of the United States of America ; 
to Pachuca, Mexico ; to the Redjang Lebong district, in Sumatra ; and to certain ancient 
mining fields of Transylvania in Europe 
I'— Waihi-Tairua 



Acknowledgments. 

It gives the writers pleasure here to record their appreciation of the courtesy which 
they have received from the various superintendents, mine-managers, individual pro- 
spectors, and niining-men generally throughout the subdivision during the course of their 
investigations. 

To the officers of the Dominion Laboratory all the chemical analyses submitted in 
this bulletin, except where stated to the contrary, are referable, and the MTiteis appre- 
ciate the despatch with which the various reports were furnished. 

Officers connected with the Work. 

The topographical work, upon which the maps accompanying this report are mainly 
based, was commenced by Kenneth M. Graham in October, 1908, and completed in 
Februarv', 1911. Mr. Graham was assisted during the greater part of the survey by 
Wilham H. Coulter, now an officer of the Lands and Survey Department, and at a later 
stage by Henry S. Whitehom. 

For the draughting of the maps George E. Harris, draughtsman, is almost entirely 
responsible. 

The geological work has been done conjointly by the two writers (J. M. Bell and 
C. Eraser), who commenced field operations in November, 1909, and completed them in 
March, 1911. 

Literature. 

A considerable number of reports and papers have appeared from time to time deal- 
ing more or less directly with the geology and mining of the area comprising the Waihi- 
Tairua Subdi%'ision. The following hst may be regarded as fairly complete. Many of 
the pubhcations have been freely consulted by the writers. 
The abbreviations used are : — 

Rep. G.S. : Reports of the Geological Survey of New Zealand. 
Trans. : Transactions of the New Zealand Institute. 
Q.J. G.S. : Quarterly Journal of the Geological Society. 
C.-18, &c. : Refers to a New Zealand parhamentary paper. 
_ 1871. Hector, J. : " On the Geology of the Cape Colville District." Rep. G.S., pp. 98-102. 

1880. Smith, S. Percy : " On some Indications of Changes in the Level of the Coast- 

line in the Northern Part of the North Island." Trans., vol. 13, p. 398. 

1881. Cox, S. H. : " Notes on the Mineralogy of New Zealand." Trans., vol. 14. 

pp. 418-450. 

1882. Cox, S. H. : " Goldfields of Cape Colville Peninsula." Rep. G.S.. vol. 15, pp. 4-51. 

1882. Cox, S. H. : "Notes on the Mineralogy of New Zealand." Trans., vol. 15, p. 361. 

1883. Bramhall, H. : '' The Mineral Resources of New 2^aland." Trans. Liverpool 

Geological Assn. 
1887. GahTU. P. : " Handbook of New Zealand Mines." 

1887. Gordon, H. A. : " North Island Mining Generally." Mines Rep., p. 18. 
1887. Gordon, H. A. : " Treatment of Gold and Silver Ores." Mines Rep., p. 58. 
1887. Pond, J. A. : " Minerals of Cape Colville Peninsula." Mines Rep., p. 56. 
1887. Hutton, E. W. : " On the Rocks of the Hauraki Goldfield." Aust. Assn. for 

Adv. Science, vol. 1, 1887. 
1887. Skey, Wilham, and McKay, A. : " Gold : Its Formation in our Reefs, and Notes of 

some newly discovered Reactions." Aust. Assn. for Adv. Science, vol. 1, 1887. 

p. 155. 
1889. Hutton, F. W. : " The Eruptive Rocks of New Zealand." Journ. Royal Soc. 

N.S.W., vol. 23. p. 102. 



1890. Haeusler, Rudolf : " On the Microscopic Structure of the Ohinemuri Gold." 
Trans., vol. 23. p. 335. 

1892. Hector, J. : " Minerals of New Zealand." Rep. G.S., vol. 21 (Appendix). 

1893. Park, J. : " On the Occurrence of some Rare Minerals in New Zealand." Trans., 

vol. 26. p. .365. 

1894. Murray, R. A. F. : " Report on Deep Quartz Mining in New Zealand." C.-6, 1894. 

1895. Cadell. H. M. : " Gold-miniufi in thi^ Hauraki District." Trans. Fed. Inst. Min. 

Eng.. vol. 1. (Extract in C.-3. 1896. p. 81.) 

1896. Campbell. J. : " The Goldfi.'lds of the Hauraki Peninsula." Trans. North of Eng. 

Inst. Min. and Mech. Engineers, 1896. 

1897. McKay, A. : '" Report on the Geology of the Cape Colville Peninsula, Auckland." 

C.-9, 1897. (Editorial on same. N.'Z. Mines liecord. vol. 1. p. 278.) 
1897. Park, J. : •• The Geology and Veins of the Hauraki Goldfield." Trans. N.Z. Inst. 

Min. Eug., 1897. (E.xtract. A'.Z. Mines Record, vol. 1, p. 168.) 
1897. Wilson. G. : " On some Differences that distinguish the Goldfields of the Hauraki 

Mining District."' Trans. N.Z. Inst. Min. Eng.. vol. 2. p. 17. 
1897. Campbell, J. : " Volcanic Zone of the Hauraki Goldfields." Scottish Geol. Mag., 

p. 246, 1897. 
1897. Wauchopc, J. A.: "The Goldhelds of the Hauraki District." Trans. Fed. Inst. 

Min. Eng.. vol. 14. pp. 19-45. 

1897. McCombie. .J. : " Treatment of Ore in the Hauraki Goldfield." Trans. N.Z. Inst. 

Min. Eng.. 1897. (Copied by .V.Z. Mines Record, vol. 1. p. 399.) 

1898. Don, J. R. : " The Genesis of Certain Auriferous Lode.s." Trans. Amer. Inst. Min. 

Eng., vol. 27. 
1898. Scliiff. F. : " Les Mines d'Or de la Nouvelle Zelande." Publication du .Journal de 

Genie Civil, Paris. 
1898. McKay, A. : " Geological Survey of Cape Colville Peninsula." Progress Rep.. 

1897-98. C.-9. 1898. 

1898. Perham. T., and Wilson. G. : " Reports on Water-conservation on Hauraki Gold- 

field." C.-4 and C. 4a, 1898. 

1899. Park, J., and Rutley, F. : " Notes on the Rhyohtes of the Hauraki Goldfield, 

New Zealand." Q.J.G.S.. vol. 55, p. 449. 
1899. Bromly, A. H. : " Treatment of Gold-ores in the Hauraki Peninsula." Eng. and 
Min. Journ.. New York. (Copied. C.-3, 1899. p. 181.) 

1899. McKay, A. : " Report on the Pumice-stone Deposits of the Middle Part of the 

North Island." C.-9, p. 16. 

1900. Rutley, F. : " Additional Notes on some Eruptive Roi ks from New Zealand." 

Q.J.G.S.. vol. 56, p. 493. 

1901. Park, J. : ' On the Secular Movements of the New Zealand Coast-hne." Trans., 

vol. 34. p. 440. 

1902. Park, J. : ' The Geology of Mines and Minerals." Otago Daily Times and Witness 

Newspaper Company (Limited). 
1902. Morgan. P. G. : "Note on the Geology. Quartz Reefs, and Minerals of the Waihi 
Goldfield." Trans. Aust. Inst. Min. Eng.. vol. 8. p. 166. 

1904. Morgan, P. G. : " Water in the Hauraki Goldfield. New Zealand." Eng. and Min. 

Journ.. New York. 15th Sept., 1904, p. 429. 

1905. McKay, A., and Sollas. W. J. : " Rocks of the Cape Colville Peninsula." 1905-6 

vols. 1 and 2. 
1905. Park, J. : " Thermal Activity in its Relationship to the Genesis of Certain Metal- 
liferous Veins." Trans., vol. 38, pp. 20-33. 



6 

1905. Lindgrcn, Waldemar : "The Hauraki Uoldfield, New Zealand." Eiig. and Miu. 

Journ., New York, 2nd FebiuaiV: 1905, p. 261. (Copied, N.Z. Mines Record, 

vol. 8, p. 370.) 
1905. Morgan. P. G. : "The Hauraki Goldfields." N.Z. Mines Record, vol. 8, p. 465. 

(See also Eng. and Min. Journ.. New York, 4th May, 1905, p. 861.) 

1905. Marshall. P. : " The Geography of New Zealaiid."' Pul>lishers. Wliitconibe and 

Tombs, Welhngtou, N.Z. 

1906. Galvin, P.: "The Mining Handbook of New Zealand." (Preface by Hon. James 

McGowan.) 
1906. Bell, J. M. : " The Salient Features of the Economic Geology of New Zealand." 

Economic Geology, vol. 1, No. 8. 
1906. Park, J. : "A Text-book of Mining Geology." PubUshers. Macmillan and Co. 

1906. Loughnan, R. A. : " The First Gold-discoveries in New Zealand." Government 

Printer, Welhngton. (Reprint from N.Z. Mines Record, vols. 9 and 10.) 

1907. Fraser, C, and Adams. J. H. : " The Geology of the Coromandel Subdivision, 

Hauraki, Auckland." Bulletin No. 4, N.Z. G.S. (New Series). 

1907. Bell, J. M. : " The Mineral Wealth of New Zealand." Journal of the Royal 

Colonial Institute. 

1908. Bell, J. M.. and Fraser, C. : " The Great Waihi Gold-mine." Canadian Mining 

Journ., vol. 29, 1908, pp. 388 and 420. 

1908. Bell. J. M.. and Fraser, C. : " The Tairua Goldfield." Australian Mining Standard, 
No. 39, 1908. 

1908. Maclaren, J. M. : " Gold : Its Geological Occurrence and Geographical Distribu- 
tion." Pubhshers, The Mining Journal, London. 

1908. Bell, J. M. : " New Zealand as a Mining Country." Australian Mininy Standard, 

No. 25, 1908. 

1909. Bell, J. M. : " Economic Geology of New Zealand." Trans. Aust. Inst. Min. Eng., 

vol. 13. 
1"909. Park, J. : " History of Mining in New Zealand." Minincj Journal. London. August, 
1909. 

1909. Finlayson, A. M. : " Problems in the Geology of the Hauraki Goldfields, New 

Zealand." Economic Geology, vol. 4, No. 7, 1909. 

1910. Finlayson, A. M. : " The Ore-deposits of Waihi, New Zealand." The Mining 

Magazine, London, April, pp. 281-86. 
1910. Bell. J. M. : " The Waihi Goldfield." Proceediniis, Aust. Inst. Min. Eng., vol. 7, 

August. 
1910. Fraser, C. : " The Geology of the Thames Subdivision, Hauraki, Auckland." 

Bulletin No. 10, N.Z. G.S. (New Series). 
1910. Jarman. A. : " Silting at Waihi." Mining Magazine, Sept., 1910, p. 191. 

1910. Morgan, P. G. : " The Igneous Rocks of the Waihi Goldfield." Trans., vol. 43. 

1911. Gilmour, J. L., and Johnston, W. H. : " Mining Methods in the Waihi Mine." 

Trans. Aust. Inst. Min. Eng., 1911. 
1911. Fyfe, A. : " Metallurgical Process of the Grand Junction Gold Company (Limited), 

Waihi." Trans. Aust. Inst. Min. Eng., 1911. 
1911. Gauvain, W. P. : " Pumping Machinery for Mines, with Special Reference to the 

Plant at the Waihi Mine." Trans. Aust. Inst. Min. Eng., 1911. 
1911. Banks, E. G. : " Milhng and Treatment at the Waihi Mine, N.Z." Trans. Aust. 

Inst. Min. Eng., 1911. 
1911. Aitken, R. M. : " Waihi-Paeroa Gold-extraction Company (Limited)." Trans. 

Aust. Inst. Min. Eng., 1911. 
1911. Bell, J. M. : "The Hauraki Goldfields, N.Z." Trans. Aust. Inst. Min. Eng., 1911. 



CHAPTER II. 
HISTORY AND TECHNOLOGY OF MINING. 



Page Page 

History of iliiiiiig Development . . . . 7 .Mining anil Treatment of Ore* . . 18 

Mineral Production . . . . .17 lunancial Conditions . . . . 2'1 

History ok Mixixcj Development. 

Although all tlic more important mining districts of Hauraki are confined to an area 
measuring aljout sixty miles by twenty miles, considerable time-intervals elapsed between 
the gold-finds which brought these several camps into existence. 

In the year 1852 the initial discovery of gold in Hauraki. if not in New Zealand, was 
made at Coromandel ; and from that date up to the present time this centre has 
experienced all the ups and downs which inevitably attend the mining of veins of the 
bonanza or "specimen-stone"" type. Ti'.e total production of Coromandel and its vicinity 
is valued at about £1.750,000. (See Bulletin No. 4.) 

In 1867 (loth August) the strike of bonanza veinstone of phenomena! richness at 
Shotover Creek. Thames, was the signal for the greatest rush of diggers that Hauraki has 
ever experienced. The principal ore-deposits at Thames, although more extensive than 
those of Coromandel, are of the same type, and the history of its mining developnu'nt 
from the earliest times to the present day proves analogous. The value oi the total 
production of Thames and surrounding areas is estimated at £7,100,000. (See Bulletin 
No. 10.) 

As early as the year 186'.) the intrepid prospector, with experience gained on the 
Thames and Coromandel bonanza fields, pushed southward and eastward to Ohineniuri, 
hoping to discover fields rivalling in richness the two older centres. As subsequent 
events proved, however, he wati doomed to disappointment. In Ohinemuri he was to enter 
a field where mining development meant a fairly heavy capital expenditure almost from 
the outset ; where even the best ore carried but a few ounces of gold to the ton, instead of, 
as at the Thames, "specimen-stone" valued at ounces to the pound. In Ohinemuri, too, 
the pioneer found his initial explorations barred not only by natural difficulties presented 
by a rough, heavily bushed, trackless country, but by the harassing tactics of the Maoris, 
who strenuously opposed the incursion of the white man into territory not ahenated to the 
Crown. Some of the more daring of the " fossickers," however, who managed to elude the 
vigilance of the Maoris, made a reconnaissance of the forbidden land, and returned with 
glowing accounts of the promising lodes they had discovered. For over five years the 
diggers anxiously awaited the conclusion of the negotiations between the Government and 
the Natives regarding the opening of Ohinemuri as a goldfield. The Proclamation declar- 
ing the field open was read on the 3rd March, 1875. The following is the interesting 
retrospect of the occasion contributed by John McCombie : — 

" At an early hour upon that day there was great excitement at Mackaytowii, 
where the headquarters of the Warden's Department was then located. It was announced 
through the medium of the Government Gazette that the field would be open for pegging 
at 10 a.m. The apphcations for miners' rights were received by the Warden's clerks 
on the previous evening, when tickets were given to those who paid for ' rights ' for 
themselves and their mates. These tickets were all numbered, and the appUcants were 
told that they must present themselves and their tickets at the Warden's office at 10 a.m. 



sharp on the following morning, when the ' rights ' would all be issued simultaneously. As 
the hour for reading the Proclamation approached, the excitement intensified, and at 
9.30 a.m. there must have been fully twelve hundred diggers standing closely packed 
together in front of the canvas shanty which did duty as a Warden's office. About 
9.55 a.m. Warden Frascr mounted an improvised platform, and, after a brief address, read 
the Proclamation declaring the field open for gold-mining. The struggle To obtain the 
miners' rights, followed by the helter-skelter down the hill, across the Ohinemuri River 
and up the opposite bank, can better be imagined than described. Just picture eight 
hundred excited men starting all together from one place at a given signal, the track 
going dovni a steep bank, across a mountain torrent, and thence up another abrupt 
incline, the goal being the Prospectors' Claim at Karangahake. . . . Upon reaching 
the ground marking-off was the order of the day, and in a very brief space of time 
there was a perfect forest of pegs surrounding the Prospectors' Claim, which had been 
reserved some days prior to the date of the opening."* 

Karangahake, although a portion of the Ohinemuri County, is outside the subdivision 
under review, but, as the wild picturesque gorge in which it is situated is the gateway to 
Waihi and Waitekauri, the foregoing narrative is of interest. It may also be mentioned, 
en passant, that the results of the earher mining operations at Karangahake proved disap- 
pointing, and not mi til 1882 were discovered the Talisman and Crown veins, which gave 
permanency to mining in tliis locahty. 

The Waihi-Tairua Subdivision encloses several mining camps, practically all of which 
have come into existence since the official opening of the Ohinemuri portion in 1875. As 
the history of most of these camps is synchronous, that of each locahty is more conveniently 
traversed separately. 

Waitekauri. 

This is the oldest mining centre of the subdivision. Even prior to the year 1870 some 
prospecting had been done here, as Sir James Hector, who made a geological recon- 
naissance of Ohinemuri in April of that year, refers to the existence of prospecting- 
drives on small leaders of quartz. The pioneer prospectors had discovered " trails of 
gold " in the creeks on the western side of the valley, but, faihng to locate any defined 
reefs, had abandoned the area. Mr. McCombie, writes : " Whilst the pegging mania was 
raging at Karangahake, a small party of men led by a prospector named Leahy might 
have been seen wending their way in the direction of Waitekauri, where they marked 
off several claims, which were subsequently amalgamated and formed what was known as 
the old Waitekauri Company's mine."f 

The Waitekauri Company, financed principally in Auckland, the provincial capital, 
further exploited the reef discovered by Leahy. This reef measured from 5 ft. to 25 ft. 
in width. A battery of forty stamps was erected. For some time the average yield 
was satisfactory, the outcrop portion of the reef at the "Big Blow" yielding ore from 
which over £4,000 was paid in dividends. Gradually, however, the returns fell below the 
profit-point, the company became financially involved, and before October, 1880, the mine 
and battery were assigned to the mortgagees. Messrs. Brown and Bleazaid. The mine 
was then divided into blocks and let on tribute. " From the very outset several 
parties of tributers did remarkably well — notably, Butler and party and Holhs and 
party, who took bullion to the value of £20,000 out of their respective tribute sections 
within a period of eighteen months. "J The rich ore mined by the tributers, some 
returning over £30 per ton, was derived from a strong hanging-wall branch of the main 
reef worked by the company. 



* Mines Record, vol. 1, pp. 33 and 34. f Mines Record, vol. 1, p. 71. j Mines Record, vol. 1, p. 72. 



9 

In 1890 the Waitekauri Mine and battery, which were still l)eing worked by 
tributers with only moderate results, were purchased by Thomas H. Russell, a gentleman 
to whose foresight and enterprise Ohinemuri mining owes a great deal. The water- 
power rights and the battery proved a more important asset than the mine, which, on 
the whole, has since 1890 never paid for development. In June. 1891. an important 
discoverv of profitable ore was made at Te-ao-maranui. on the Komata-Waitekauri 
Range, and in September. 1892, a similar discovery was made at (Jolden Cross, in the 
headwaters of the Waitekauri Valley. Both of these new prospects were purchased by 
Mr. Russell, who formed small companies to develop them. In 189-1. recognizing that 
more capital was required, Mr. Russell effected the sale of the Waitekauri. the Komata 
(Te-ao-niarama), and the Golden Cross claims to the Waitekauri Gold-mining Company, 
London (capital, £150.000). The mining operations undertaken by this company were 
mainly concerned with the development of the Golden Cross Claim, which was con- 
nected by tram with a new forty-head battery and cyanide plant erected on the site of 
the old mill in Waitekauri Townshij). Further exploration was done in the old Waite- 
kauri Claim, which was connected with the new mill ; and the development of the 
Te-ao-marama Claim on the Komata side of the range was also undertaken. From 1895 
to 1900 were the prosperous days of Waitekauri. the premier company employing about 
350 men and paying dividends to the amount of £84,035 from a bullion output valued 
at £309,769. Almost the whole of this output was obtained from the Golden Cross 
Claim. A striking fact in the history of Waitekauri. however, is the abruptiu^ss with 
which the metal-output of the Golden Cross Miiu) fell from a maximum value of over 
£80,000 in the year ending 31st March. 1900. to almost nil by the end of 1902. The 
company abandoned this mine in 1904. and also sold the partly developed Te-ao-marama 
Claim to the Komata Reefs Company, the owners of an adjoining claim. 

While the history of Waitekauri is in great part the history of the companies that 
have owned the old Waitekauri and the Golden Cross mines, a great many other claims 
have been worked from time to time. A few of these claims proved profitable in the 
earher days of the field. Most of them, however, have never paid for development. 
The name of the Young New Zealand (now the Maoriland) is alone worthy of mention, 
as this claim yielded to the early proprietors rich outcrop ore to the value of about 
£24,000. At the present time the Maoriland, the Jubilee, and the Scotia claims, all in 
the vicinity of the original Waitekauri Mine, together with the Golden Cross Claim, at 
Whakamoehau, are the only areas on which mining operations are in progress. The 
number of men now employed in the whole district does not exceed forty. The value 
of the gold-silver output from the Waitekauri Valley may be assessed in round figures 
at £500,000. 

Owharoa. 

Owharoa, Ijing between Karangahake and Waitekauri. on the north side of the 
Ohinemuri River, has been the scene of intermittent prospecting and mining since 1875. 
Tlie gold-silver output has been small, but certain of the blocks mined from shallow 
adit levels have yielded a profit. At present the only claim that is working in this 
locaUty is the Rising Smi. Prior to 1887 .some £50,000 worth of bullion is stated to 
have been obtained. Since 1887 the recorded output is £3,714. 

Waihi. 

The earUest mention of Waihi appears in the geological report of 1870-71 by Sir James 
Hector. Reference is made to the nature of the rock-formations and to the occurrence 
of quartz reefs in the vicinity of the north headland of Waihi Beach. Even at this 
early date (April, 1870) the marks of the prospector were in evidence, as mention is 



10 

made of " places where the ground has been tried." The first prospectors to pitch 
camp at Waihi are said to have been Daniel Leahy and Scott O'Neill, the discoverers of 
payable gold at Waitckauri. They were followed by Corbett and Marriman. Both of 
these parties confined their attention to the Union-Silverton Hill, and failed to find 
anything which appeared profitable to work. 

To John McCombie and Robert Lee, who came eastward from the Waitckauri 
diggings in February, 1878, is to be ascribed the discovery of payable gold in the 
Martha lode. This find was ultimately destined to transform the fringe of the desolate 
scrub-covered plain skirting Martha Hill into a prosperous and populous mining camp. 
The prospectors, after satisfying themselves as to the value of the outcrop of this 
lode, which measured 20 ft. wide, had within four months of the time of starting driven 
an adit 200 ft. This adit intersected the lode 60 ft. below the surface. Prospects were 
still good, and a trial parcel of 2 tons of the ore was taken to the Smile-of-Fortune 
battery at Owharoa, some six miles away. Ttiis was treated by wet-crushing and 
amalgamation on copper plates, for a return valued at £1 13s. per ton. The extractioii 
did not exceed 35 per cent, of the assay value. 

This mining proposition at Waihi, for which McCombie endeavoured to raise capital, 
did not appeal to the Auckland speculators, who were then famihar onh* with the 
Thames class of mine. The prospectors were, unfortunately, not to reap the reward of 
their discovery ; they temporarily abandoned their claim to visit Te Aroha, from whence 
news had come that a Maori, Hone Werahiko, had struck gold. In their absence two 
Coromandel prospectors, WilUam Nicholl and Robert Majurey, visited the workings, and 
were so favourably impressed with the show that they induced their friends to apply for 
several hcensed holdings on the hne of lode. This involved a plaint against McCombie 
and Lee for forfeiture of their claim on the gromids of non-workdng. Rather than oppose 
this suit the original prospectors unconditionally surrendered the ground. 

The Martha Extended Gold-mining Company (Auckland), which was formed to work 
Nicholl's and certain adjoining claims, commenced operations on the 31st March, 1883. 
A thirty-stamp battery with four berdans, driven by water-power, was erected and run 
on oxidized ore from the opencut and adit worldngs on the Martha lode. During the 
first four years 30,000 tons was treated by wet-crusliing and copper-plate amalgamation, 
for an average return of 13s. per ton. This represented an extraction of probably not 
more than 25 per cent, of the actual value of the ore. Although the veinstone was 
free-milUng, the gold occurred in such an extremely fine state of division that the 
treatment facihties available were altogether inadequate. As the company was making 
no profit, the mine and plant were let on tribute to Wm. HolUs and party, who were 
just able to make both ends meet on mill returns similar to those formerly obtained by 
the company. 

In 1890 the Martha Company's mine and plant were purchased by Thomas H. 
Russell for £3,000, and transferred to the Waihi Gold-mimng Company (Limited), 
London. The Waihi Company had been in existence three years prior to purchasing 
the Martha Claim, having been formed in 1887 to acquire from Auckland companies 
and syndicates the Union, Rosemont, Amaranth, and certain other holdings situated on 
the group of hills distant about half a mile to the south-east of Martha Hill. 

The Waihi Company undertook the development of all these claims up to the year 
1891, when a subsidiary company, the Union-Waihi, in which the parent company 
retained a controlhng interest, was formed to work the Union-Rosemont-Amaranth section. 
This subsidiary company also acquired in 1898 the Silverton Claim, which from 1885 
had been worked successively by the Silverton Gold-mining Company, Auckland, and 
the Waihi-Silverton Gold-mining Company (Limited), Glasgow. Fortune, however, did 
not favour the Union-Waihi Company, although a considerable amount of work was 



11 

done from adits aud shafts on the Union, Amaranth, and Silverton lodes, and in 1902 
finaucial considerations necessitated the property and plant being transferred to the 
Waihi Company. Since the Union- Wailii Company snspended operations httle or no 
work has been done in tliis section, and the deepest shaft measures only 667 ft. from 
the collar.* As far as can be gathered from the statistics, 70,464 tons of ore was 
milled from these claims for a return of gold-silver bullion valued at £103.563. but this 
does not cover the whole production. No di\'idends appear to have been paid by any 
of the companies that worked these properties. 

The history of mining development on the Martha lode, and on the numerous 
conjugate ore-bodies of this extraordinary vein-system that have one by one been 
revealed as underground exploration has progressed, is too well known to be traversed 
in detail. The Martha lode, even from the blocks above the adits, was capable of 
supplying a large tonnage of good ore. yet the initial operations of the company were 
only partly successful, owing to the cost of treatment and the poor extraction obtained. 
Plate amalgamation gave phue to the Washoe process, yet a recovery of only 60 per 
cent, of the assay value was recorded, and the profit made was small. The introduction 
of the cyanide process in May, 1894, however, altered the whole position, and the 
success of the company was definitely assured. 

Although the Waihi Company during the next three years proved that the Martha 
was only one of the lodes of what promised to be a persistent vein-system, no extension 
of these veins was found beyond the limits of Martha Hill. In 1897. however, the 
Waihi Grand Junction Gold Company (Limited) intersected a large lode, which proved 
to be the Martha, in shaft- workings 500 ft. below the surface of the plain lying to the 
eastward of the liill. This company, formed in England, had since 1891 been engaged 
in prospecting two separate sections of ground, one King to the east and the other to 
the west of the Waihi Company's propeity. 

The history of the Junction's mining development, even after the finding of the 
veins, has been one of alternate periods of progress and of marking time. The main 
bar to expeditious development has always been the drainage position. The vein- 
l)earing rock, although outcropping in the adjoining Waihi property, is in the Junction 
overlain by from 4(X) ft. to 8(J()ft. of more-recent rocks, a feature which constitutes the 
Junction a relatively deep-level property. The rate of progress in opening level after 
level in the Junction has been dependent solely upon the rate of downward explorations 
in the Wailii Company's mine, because the Jimction Company has not felt justified 
in taking the initiative as regards the drainage of the extensive vein-system. 

In the year 1906 (20th August) the Waihi Grand Junction Company started its 
forty-head mill, and up to the 31st December of that year crushed 8,144 tons of ore for 
bulhoii valued at £13,795. Two claims, the Waihi Consols and the Waihi South, upon 
which Auckland companies had done some shaft-sinking and diamond-drilling without 
success, were during tliis year acquired by the Grand Junction Company, and added to 
what is known as the " Western section." 

The Waihi Mine closed the year named (1906) with an ou£put valued at £837,927, 
having increased its yield in one decade from 34,410 tons, valued at £135,151 (1896), 
to 328,866 tons, valued at £837,927 (1906). Stamps to the number of 330 were now 
dropping for this company on ore from sixteen different lodes. The mine was being 
opened at the No. 8 level, 850 ft. from the surface, with results even more satisfactory 
than were obtained at the levels overhead. 

The Wailii and Waihi Grand Junction, although the sole producers, were not the 
only companies at this time operating in Waihi. The Waihi Extended Gold-mining 
Company (Limited), wliich owned a claim on the eastern hne of the Martha lode, was 



• " Papers and Reports relating to Alinerals and Mining " (Mines Report), G-3, 1902, 



38. 



working from a shaft at a deptli of 632 ft. This company had been in operation since 
1895, and discovered in 1903 a branch of the Martha lode at a depth of 500 ft. from 
the surface. The owners of the Waihi Consolidated Claim and the Walker's G'gantic 
claims, eastward of the Extended property, were attempting to reach the deeply l)uried 
surface of the vein-bearing country, while the Waihi Beach United Gold-mining Company 
was engaged in prospecting certain reefs intersecting the rhyoUtes of the coastal ridges 
about six miles from Waihi. The year 1906 is also noteworthy for the opening* of the 
Government railway connecting Waihi and adjoining mining camps with the general 
railway system of the North Island. 

The period 1907-9 was one of steady progress on this goldtield. Although no new 
claims were added to the hst of producers, the value of the bullion output was steadily 
increasing, and for 1909 totalled £1,070,341, the Waihi Company contributing £959,594 
and the Grand Junction Company £100,688. t In the Waihi Mine the exploration of the 
No. 9 level, 1,000 ft. from the surface, was in progress, and the Grand Junction was 
successfully opening No. 5 level at a corresponding horizon. 

The year 1910 is memorable as marking the first year in the history of the Waihi 
Mine in which the output showed a decrease, as compared with that of the previous 
year. The decrease is only £33,494. but it is evident that still lower yields are to be 
expected. This is attributable to the fact that the lowest level exploited. No. 9, has 
revealed much less ore than did the level above. The total value of the output from 
the mine up to the 31st December. 1910, is £9,106,318 ; and out of this. £4.251,554 has 
been paid in dividends. These figures constitute a record equalled by few gold-mines. 

The Grand Junction Company, after incurring a heavy expenditure in develop- 
mental work, has just reached the profit-making .stage. It is now pushing exploration, 
as far as the general drainage-level will permit, with a view to ascertaining the full extent 
and value of the several lodes. The yield for the year 1910 is valued at £133.315. 
This is a material advance on the value of the output of previous years, and the 
payment of the first dividend (5 per cent, on the capital) is announced. 

All the other Waihi claims are still in the prospecting stage. Shaft-sinking is in 
progress in the Waihi Extended and the Waihi Reefs Consohdated. while preparations 
are being made in certain claims still farther to the eastward to test the nature of the 
country by boring. 

The history of the camp, which is entirely dependent upon mining, has up to 
the present (1910) been one of steady progress. Little more than three decades has 
elapsed since the district was inhabited by only a few Maoris ; to-day about eight 
thousand persons, distributed between Waihi and Waikino,^ draw their means of 
UveUhood directly or indirectly from the exploitation of the veins. The discovery of gold 
was not marked by a " rush " of diggers such as most mining centres have experienced : 
yet Waihi is to-day the most populous mining town in New Zealand, and counts among 
her possessions a mine which still ranks among the great gold-producers of the world. 

The total recorded value of the bullion derived from the Waihi district up to the 
end of 1910 amounts to' £9,649.345. 

Komalu. 
The discovery of payable gold in Komata was made by Tilsley and Worth in June, 
1891, the trial crushing of 1 ton of ore at the Thames School of Mines vielding £21. 
This prospect, the Te-ao-niarama Licensed Holding, was purchased for £3,000 by 
Thomas H. Russell, and a further test-parcel of 100 tons mined from adits was packed 
and sledged to the Waitekauri battery for a return of £700. The Komata Gold- 



* Trains, however, were run by the Public Works Department from the 9th November, 1905. 

fThe Waihi-Paeroa Gold-oxtraction Company (treating tailings) was the only other producer. 

i The site of a 200-stamp unit of the Waihi Company's mill, ancl distant about five miles from Waihi Town. 



13 

mining Company (Limited), which was then formed locally to develop the claim, 
connected it by tram with the battery named, and by 1893, when the claim was purchased 
by the Waitekauri Gold-mining Company (Limited). London. 6.487 tons had been 
milled for bullion valued at £33.377. 

In 189-1: the Komata Reefs Gold-mining Company (Limited). London, acquired several 
claims adjoining Te-ao-marama. On certain of these profitable ore had been discovered 
in veins, which proved to be an extension of those in the Te-ao-marama. The new 
company expended much money on development, and by 1897 had a twenty-stamp 
mill and cyanide plant in operation. The peld from these claims reached a maximum 
in the following year, when 5,435 tons of ore produced bullion to the value of £17,795. 
From this time the results were disappointing, but the company in 1901 secured a new 
lease of life by purchasing the adjoining Te-ao-marama Claim from the Waitekauri 
Company. Developmental work had been done in this ground by the vendor company. 
but no ore had been crushed. The Komata Reefs Company was now in a position 
to augment its returns materially, and in the year 1907 the production reached a 
maximum of £46,958. The company's total output to the end of 1910 was valued at 
£369,017, and dividends have been paid to the amount of £33.333. 

Numerous claims in the Komata Valley, in addition to those mentioned, have been 
worked intermittently l)y private indi^^duals or companies. These include the Komata 
Amalgamated, Komata Queen, Byron Bay. and Just-in-Time. Nothing payable was 
unearthed on any of these holdings. 

The total value of the gold-silver production of Komata Valley from date of 
discovery to the end of 1910 is. according to the available statistics. £402,394. 

Maratoto. 

The discovery here of a large quartz reef carrying at its outcrop seams of rich 
ore was made in August, 1887, by Richard McBrinn. Samples forwarded to the 
Colonial Laboratory assayed gold 80oz. and silver 2.146 oz. per ton. A "rush" took 
place, and sixty-five Ucensed holdings, aggregating 1,287 acres, were pegged. The reef 
was traced for nearly two miles, and presented what were considered good prospects 
at several points along its outcrop. It was soon recognized that the richer mineral ore 
— which, as a matter of fact, contained argentite and some hessite (the sulphide and 
the telluride of silver) — was not amenable to the amalgamation process. Reports 
state that IJ tons sent to Sydney realized £380. and that 3(» tons were sold to a 
Freiburg buyer for £420. However, the Maratoto Gold-mining Company, formed to 
work the prospector's claim, erected a small pan-amalgamation plant, and commenced 
crushing. The results were disappointing, and most of the claims in the valley, which 
were held mainly on the strength of the prospector's claim, were forfeited prior to the end 
of 1888. In 1891 the old Maratoto Company discontinued operations, and for four years 
only a few prospectors and tributers remained in the valley. With the mining revival 
in 1895, however, attention was again directed to the Maratoto district, and in the 
following year the Maratoto Gold-mining Company (Limited), of Auckland, and the 
Hikutaia Gold Syndicate, of London, were formed to work respectively the old Maratoto 
Claim in McBrinn's Creek, and the Maratoto United Claim in Peel's Creek. Both of these 
claims are on the same line of reefs. It was hoped that by systematic development and 
the use of the cyanide process profitable results would be forthcoming. In 1903, how- 
ever, both the companies ceased operations, the returns proving unprofitable. The 
development-work done by the Hikutaia Gold Syndicate in the Maratoto United Claim 
proved the existence of a fairly large tonnage of ore, assaying about 15s. per ton. 

Near the Maratoto-Waitekauri Saddle, and adjoining the Golden Cross Claim, is 
the St. Hippo Claim, worked from 1895 to 1900 bv the Waitekauri Extended Gold- 



14 

mining Company (Limited). London. A substantial forty-stamp mill with cyanide 
plant was erected in the Maratoto Valley, and connected with the mine by aerial 
tram. Ore amounting to 6,017 tons was crushed from a large reef, for bullion valued 
at £6,149. Since no profit was being made, operations were discontinued. 

In 1906 the New Maratoto Company (Limited) purchased the Wait«kauri Extended 
Company's mill, and made an unsuccessful attempt to work at a profit the old 
Maratoto Claim. Bullion to the value of only £954 was won before the company went 
into liquidation. 

At the present time the old Maratoto and the Maratoto United claims are held bv 
prospectors, while two areas in the south-east side of the valley are being worked — one bv 
the Silverstream Gold and Silver Mining Company, and the other by the Tellurides 
Proprietar\' (Limited). The former company is crosscutting to open up blocks on the 
Julia and Silverstream reefs, both of which have afforded, from shallow adits, parcels 
of rich argentiferous ore. 

The history of mining in Maratoto has been one of repeated failures, in part 
owing to the high co.st of treating relatively low-grade argentiferous ore, and in part to 
the ore giving place in certain of the low-level adits to a barren calcific veinstone. 
The value of the recorded output from the valley is about £25,900. 

Puriri, Omahu, and Kirikiri. 

The fact that the Puriri Valley was auriferous was, ov\'ing to its proximity to 
Thames, discovered prior to the end of the year 1868. The lower Puriri area, however, 
was that which claimed the most attention, and is described in Bulletin No. 10, which 
deals with the Thames Subdivision. Between this part and the comitry drained by 
the actual headwaters of the stream, and regarded as part of the Neaves\nlle area, only 
a few insignificant prospects have from time to time been w^orked by small syndicates 
and private indi^^duals. No work is now in progress. Mining in the adjoining Omahu 
district has been carried on occasionally since 1899, but the total recorded production 
amomits to only £1,800, and the area is at present deserted. In 1895 a reef carrying small 
pockets of " specimen-stone " was discovered in the comitry drained by the head- 
waters of the Kirikiri. The prospector's claim has been worked intermittently by 
small companies up to the present time. The total production, however, from the 
date of discovery up to the end of 1910 amounted to only £1.696. 

Tairua and Neavesville. 

Gold is reported to have been discovered in Tairua in April of 1875. but probably 
this refers to the Neavesville area, which overlooks the headwaters of the •' Fourth 
Branch " of the Tairua River. In this locality and in the neighbouring Champion 
area, within the Puriri watershed, veins and minerahzed pipes afforded some high- 
grade ore, the value of which prior to 1886 is not recorded. From the year mentioned, 
however, until 1895 the total yield amomited to only £1,875. 

In 1895 the discovery of gold in the area now included in the Tairua Broken 
Hills Claim was reported, a trial crushing yielding, from 1 ton of ore, bullion to the 
value of £69. This was the signal for a " rush," and the staking of a considerable 
stretch of adjoining country. The Broken Hills Claim was acquired by a London 
syndicate, which spent money freely, and purchased a twenty-stamp mill before any 
continuous run of payable ore had been found. Operations were suspended in the 
claim in 1898, and on none of the numerous adjoining claims had any noteworthy 
discovery been made. 

In 1899 the Broken Hills Claim was purchased at auction by an Auckland 
syndicate, and a company was formed further to prospect it. Initial operations were 



15 

unsuccessful, but in 1901 profitable ore was disoovcrerl in tlio lower levels. Up to 
the end of 1910, 44,355 tons of ore was raised and cyanided for bullion valued at 
£90,678. and out of this £24,710 was paid in dividends. During the 3-ear 1909 the 
returns diminished owing to the blocks opened on the various reefs becoming exhausted, 
and attention is at present directed to opening blocks below fhe adit. The Tairua Broken 
Hills Company, it may be remarked, is the only one operating in the subdivision which 
has paid dividends from the exploitation of veins enclosed in rhyolite country. 

The satisfactoiy residts obtained by the Broken Hills Company gave impetus to 
the operations of several other companies prospecting ground in Lower Tairua. Of these, 
however, only two are now in existence — namely, the Tairua Golden Hills and the 
Tairua Monarch Consolidated. The former company has expended a considerable 
amount of money in opening its mine and erecting a mill, but up to the end of 1910 
a return of only £253, deriv^ed from 650 tons, is announced. The Tairua Monarch 
has a small mill in course of erection. 

Sul)se(|uent to 1902 Neavesville was also the scene of active mining operations. 
The (Jolden Belt Gold-mining Company (Limited) was formed in the year named to 
work ground which had afforded gold to earlier prospectors, and in 1905 the Champion 
Gold-mining Company (Limited) undertook the further development of the adjoining claim, 
which is reported to have yielded profitable ore in former years. The Golden Belt Company 
erected a battery of forty stamps, and the Champion Company one of ten stamps. Up to 
the end of 1910 the value of the returns credited to these companies amounted to only 
£14,612 and £746 respectively, and operations are at present in progress on a very small scale. 

The Chelnisford Gold-mining Company, fonned to work a claim about two miles 
east of Neavesville. had ten stamps crushing intermittently from 1901 to 1905, for 
returns totalling £5,446. Impoverishment of the veins in depth led to a cessation of 
operations, and although a company — the Taihoa — was subsequently formed further to 
prospect the ground, no profitable ore was discovered. 

Ohui. 

At Ohui, about four miles from Lower Taima, the earliest gold-discovery was 
made by James McGregor and party in 1893, when 8 tons of ore shipped to Thames 
yielded 17 oz. lOdwt. of bullion. Since then prospecting and mining has been carried 
on intermittently, but to the end of 1909 the total recorded value of ore crushed 
did not exceed £350. The country is one of little relief, but so far the Phcenix is the 
only claim in which a shaft has been sunk, and operations here at the 80 ft. level 
were, owing to the inadequate pumping machinery provided, prematurely abandoned. 

Whnnqnmntn and Whnrehtwn. 

Auriferous quartz was discovered in Whangamata several years prior to 1887, but 
little work was done until the year named, when the Goldwater Gold-mining Company 
was formed to prospect a reef aV)out 3 ft. wide. Before the end of 1889 this company 
had discontinued operations, having treated 31^ tons for 1,271 oz. of buUion, containing 
a high percentage of silver. Although a considerable area of ground has been staked 
at various times, the only producer worth mentioning was a claim known successively 
as the Wentworth, Mananu, and Auckland. The development of this claim was under- 
taken in 1897 by the Haurald Peninsula Exploration Company (Limited), of London, and, 
from the year 1900 to 1904. 7,099 tons of ore was mined and milled for £18,093. The 
property was then acquired by the Auckland Gold-mining Company, and in the following 
three years 2,774 tons of ore yielded bullion valued at £10,131. The claim is now 
abandoned, and the twenty-stamp mill has been removed. 

Mining in the Wharekawa Valley dates from 1895, when Edward Withers discovered gold 
in a 7 ft. reef, and staked the Luck-at-Last Claim. One ton of ore sent to Thames reahzed 



16 

over 15 oz. of bullion. In the follo\ving year the Whangamata Proprietary- (Limited), 
London, purchased the claim, and. after further developing the reef, erected a treatment 
plant consisting of three Krupp niills and a cyanide plant. IVIilUng was commenced 
in June, 1899. and continued up to 1901, 10,768 tons of ore returning bullion valued 
at £17.720. In 1902 the proprietary disposed of the claim, and in the following 
year the machinery and plant were removed. At present an Auckland company, the 
Luck-at-Last, is dri\'ing a low level to further exploit the same reef. Many small 
prospect-workings were opened in the vicinity of the Luck-at-Last at Wharekawa, 
but no discoveries of ore were made. In the headwaters of the Wharekawa, however, 
about four miles from the Luck-at-Last, the Phoenix-Pukewhau Claim in 1895, and 
the Waimangu Claim from 1904 to 1907. gave small returns from parcels of picked 
ore. which were crushed at Thames. 

Gumtown. 

In 1898 the discovery of gold in the elevated rhyohtic countr}' lying between 
the Rangihau and Kapowai streams near Gumtown attracted attention to this area, 
formerly little known, save to the bushman and the gum-digger. With the exception 
of the quartz reefs of the Welcome Jack Claim, the nature of the deposits were unfamihar 
to the prospectors. They consisted rather of reticulated veinlets, clay and rubble 
filled fissures, and open crevices in the altered silicified rhyolitic tuffs. The walls of 
many of these fissures and crevices were peppered with " showy " finely di\"ided gold, 
and the richness of the field was loudly proclaimed by the sanguine prospector. Sub- 
sequent batter)- returns proved, however, that the bulk of the ore was low grade. Of 
the several companies which have worked claims since the year 1899 only one is now 
existent — namely, the Kapowai. The total production of the Gumtown claims up to the 
end of 1910 amounted to £U.062. 

Summary. 

The history of prospecting and mining development in the Waihi-Tairua Subdivision 
as a whole is seen to cover a period of three decades and a half. Discoveries have been 
made at many localities, from Waihi and Waitekauri in the south to Gumtown in the north. 
Most of these gold-finds, excepting, strange to say, that at Waihi itself, were immediately 
followed by the usual " rush " of diggers and the widespread staking of claims. 

Up to the year 1894 progress was almost solely dependent on local capital, the one 
exception being the Waihi Mine, which was financed by an English company. Beyond 
the profits derived from the small patches of the richer outcrop ore, mining in the 
subdi\'ision was conducted with little or no profit. Few of the companies formed to 
further exploit the various reefs discovered by the prospector reached the dividend Usts, 
and probably none repaid the capital expended in development. Failure in many cases 
was due to the impoverishment of the ores in depth : in others, again, to the inefficient 
methods of mining and milUng then in vogue. 

In 1894 the markedly successful application of the cyanide process by the Waihi 
Company to the treatment of ore otherwise unprofitable not only estabhshed the 
Martha Mine as a great profit-making concern, but caused the EngUsh investors to seek 
for other promising areas in Hauraki. The incentive to invest was increased by 
the discovery in the same year of extensive and wonderftilly rich bonanzas in the 
Hauraki iVIine, a London-owned property at Coromandel, in the northern part of the 
Hauraki Peninsula. This culminated in a veritable mining " boom." An enormous area 
of coimtrj-, of proven auriferous character and otherwise, was pegged, and company- 
promoting, much of which was absolutely unwarranted, was the order of the day. The 
net result, however, was that a decided impetus was given to prospecting and mining 
generally. Ntmierous EngUsh and local companies were organized to develop claims in 
the Waihi-Tairua Subdivision, in common with the whole Hauraki Goldfield, and for five 



17 

or six years prospecting and mining was energetically carried on over a wide area. As 
in all such periods of mining excitement, it cannot be affirmed that the expenditure of 
capital was in all cases warranted, or. again, that where prospects offered, mining 
operations were intelligently directed. 

As the reader will have gathered from the detailed outline of the various mining 
centres, the results in the great majority of cases, both during the " boom " period and 
in subsequent years, can hardly be regarded as anything but disappointing. Outside of 
the Waihi centre itself, the Golden Cross Claim, which was worked by the Waitekauri 
Gold-mining Company (Limited), of London, alone proved profitable. All the other 
English-owned concerns, including the Komata Reefs (wliich, however, has paid dividends 
to the extent of £33,333), have been worked at a loss. Locally organized companies, 
moreover, have not been more fortunate ; and of these, apparently, the Tairua Broken 
Hills Company alone has returned the amount of its paid-up capital in dividends. 

The great record of the premier mine at Waihi, with its aggregate output of over 
£9,000,000 sterling, and its profit-distributions exceeding £4,250,000 sterling, has fortu- 
nately compensated for many of the miprofitable mining ventures of the subdivision. 
This mine, the Waihi, together with the adjoining property, the Waihi Grand Junction, 
which has only recently reached the profit-making stage, accounted in the year just closed 
(1910) for a vield representing £1,059,415, or over half the total value of the bullion 
exported from the Dominion.* 

MiNKRAI, PrODICTIO.V. 

The total gold-silver jneld of the Waihi-Tairua .Subdivision cannot be accurately 
stated, owing to the lack of statistics relating to the earlier years of the field. The 
following tabulation sho^\^ng the outputs from the several districts nuiy be regarded 
as a close approximation. From this it will be seen that the total production from the 
opening of the mining field to the end of the year 1910 is valued at about £10,824,304. 

District. 
Boat Harbour 
(iumtown 

Kauacranga (Hihi only) 
Kirikiri . . 
Komata . . 

Maratoto (appro.ximate) 
Ohui 

Omahu . . 

Owharoa (1887 to 1910) 
Tairua-Neavesville (1887 to 1910) 
Waihi (near approximation) 
Waitekauri (1887 to 1910) . . 
Whangamata-Wharekawa (1887 to 1910) 
Wharekirauponga 

Additional (rough approximations) — 
Owharoa (prior to 1887) 
Tairua-Neavesville (prior to 1887) 
Waitekauri (prior to 1887) 



Ore crushed, 
in Tons. 

14 


Yield. 

£ 

22 


5,270 


14,062 


« 


145 


466 


1,696 


187,716 


402,394 


23.929 


25,900 


96 


497 


1,325 


L8(X) 


5.968 


3,714 


45.692 


110,927 


4.050,746 9 


,649.345 


167,620 


397,214 


25.977 


46,563 


15 


25 


Value of Yield, 
£ 
50,000 
20,000 
100,000 


170,000t 




£10 


,824,304 



♦The yield for 1911 was £820,908. 

f Mines Handbook "" (1887), p. 281, states : " Up to the end of 1885, 40,200 oi. were exported from 
the Ohineniuri section of the Hauraki f;oldfiol(l."" 



2— Waihi-Tairua. 



18 

In addition to gold and silver, a few tons of mercury-bearing ore (cinnabar), as well 
as soni(> metallic mercury, has been exported (from Mackaytown), but tbe total value 
is almost negligible. 

MiNiXG ANT) Treatment of Ores. 

Mining practice in the Waihi-Tairua Subdivision does not differ materially from that 
which obtains on other gold-silver fields where somewhat similar conditions exist. 

As the methods adopted in localities where comparatively small veins arc being 
worked are practically the same as those described in Bulletins Nos. 4 and 10. dealing 
with the adjoining Coromandcl and Thames subdivisions, the following outline refers 
principally to Waihi, where more extensive mining and milling operations are in 
progress : — 

Mining. 

All shafts are of the vertical rectangular form, and are invariably timbered through- 
out, the larger ones with frame-sets and laths, the smaller ones generally with closely 
spaced box-sets. 

The vein-bearing rock is usually hard enough to stand unsupported in crosscuts, 
except in local areas of shattered or " swelling " comitry, and in the vicinity of faults and 
certain of the veins. 

Sawn kauri is the timber in common use for shaft-timbering and general equipment, 
but for the supports in the underground roadways and in the stopes a variety of local 
timbers — round, squared, or sawn — are employed. Imported timber — Oregon pine, 
Australian jarrah, ironbark, &c. — replaces the local timbers for special pui-poses. 

The drainage of the mines at Waihi, owing to the large volume of water to be 
lifted, involves a heavy capital expenditure for plant, renders preliminary development 
tedious and difficult, and materially increases the current mining-cost. At a depth of 
1,000 ft. the inflow from the Martha vein-system to the main pumping-station (No. 5 
shaft, Waihi Mine) amounted to 900 gallons per minute, the rate of increase below the 
shallower levels having been about 0-9 gallons per foot sunk. 

Practically the whole of the unwatering of the field has been effected by pumps of the 
improved Cornish type. Recently, however, an electrically driven three-throw ram pump 
has been erected to supplement the smaller of the two Cornish puuips at present in use. 
The sizes and capacities of these pumps are given elsewhere (see pages l-t3— 1-1). Sinking- 
pumps of various types, operated either by electricity or compressed air. are employed 
by the Wailii Grand Junction, Wailii Extended, and Waihi Consolidated companies when 
sinking for a new level. In such cases the actual intersection of the reefs — the main 
water-channels — is not attempted until they have been tapped and drained by the Waihi 
Company. 

Ventilation of the mines depends almost entirely upon the natural circulation of the 
air via downcast and upcast shafts. The existence of the six shafts and numerous 
filhng-passes renders air-conditions in the Waihi Mine satisfactory, in spite of the fact 
that the increment of temperature wth depth is fairly high. Air conveyed in pipes 
from compressors, or again from small fans or water-blasts, is required in certain 
workings, especially during the course of initial developmental work. In the Grand 
Junction Mine, where connections with the surface are less numerous, electrically driven 
fans, placed in " lay-bys " in the underground roadways, have been found effective. 
Certain of the levels of this mine are connected with the corresponding levels projected 
from the shaft of the Waihi Extended Claim, the latter shaft constituting an upcast. 
A low barometric pressure adversely affects underground air-conditions at Waihi ; but to 
a minor extent compared with Thames, where mine-gas is much more abundant. 



19 

Hoisting in the shafts of the Waihi Mine is effected by steam-driven winding- 
engines of the usual types, but in the Grand Junction electric hoists are used. Cages 
are employed, and the mine cars or trucks, holding usually about 19 cubic feet, are 
raised to the surface. One truck only is carried per trip. Double-decked cages for 
ore-haulage were tried by the Waihi Company., but were discarded as unsatisfactory, and 
at present single-deck cages capai)le of carrying two trucks per cage are being fitted at 
No. 2 shaft. The Waihi Coni])any's main winding-shaft (No. (5). however, is equipped 
with 3-ton self-dumping skips, and forty-four skip-loads have been raised and dumped in an 
hour from a level approximately 800 ft. below the brace. Underground liaulage of ore 
in the lower levels of the Waihi Mine is effected mainly by horses. In the upper 
levels of the mine, and elsewhere throughout the field, the trucks are shifted by manual 
labour. 

For shaft signalling the ordinary wire knocker-line, which has been discarded in many 
other mining fields in favour of one or other of the electrical systems, is still the method 
ernplovi'd at Waihi. 8])eaking-tubes afford means of communication between sonu^ parts 
of the Waihi Mine, and recently telephones have been fitted at the lower levels. 

Electric light is provided in both the big mines in shaft-chambers, pump-stations, 
imderground hoppers, and main underground roadways : elsewhere candles arc the sole 
illuminants. 

The several systems employed in mining the ore may be classified as follows : 
(n) Driving and widening of levels ; (6) ordinary tlatback or overhand stoping and filling ; 
(c) overhand stoping with square .sets and filling : (f/) shrinkage stoping and filling ; 
(e) taking out arches ; (/) siii-face cuttings. 

The vertical interval between the levels now preferred on the field is loKft.; the 
horizontal distance between winzes. 80 ft. Shoots oi' passes for delivering ore from the 
stopes to the levels are usually spaced about 18 ft. apart, except in the case of shrinkage 
stoping. where they are spaced ft. from centre to centre — that is, there is a pass 
between every alternate set of timbers. 

(fl.) The timbering of drifts preparatory to stoping. and after strip])ing or widening 
is completed, is usually done with ordinary sets and laths, but occasionally heavy stulls 
and laths are used instead. Saddle-back timbering has occasionally been tr.'(>d. as this 
method, like stulling. admits of the ore immediately under the level being snbse(juently 
extracted without disturbing or temporarily supporting the timbering. Notwithstanding 
these advantages, the rapidity with which the round timbers used for stulls or saddles 
decay, and th(> difficulty of replacing them in case of l)re:ikiige. has led to sets being 
preferred. 

(b.) Overhand stoping and filling accounts for the greater part of the ore mined at 
Waihi. and as both the wall-rock and the veinstone stand remarkably well no timbering 
is. as a rule, required to support the roof. Stoping widths of 50 ft. are not uncommon, 
and a vein even 80 ft. wide has been worked on this system without roof-supports. 
In mining sudi wide veins, two parallel drifts or roadways are, however, found necessary 
to handle the ore economically. The filling is always kept well up towards the 
arched roof of the stope ; and machine-drills, which of necessity give lise to much 
vibration, are often dispensed with owing to the friable character of the ore and the 
soft base afforded by filling-material. This filling is dehvered through winzes spaced at 
soft, intervals, and is trimmed along the stopes by shoveUing. The ore-passes, say, 
18 ft. apart, and the ladder-ways, about 80 ft. apart, are cribbed through the filling in 
the usual manner. SHcing and filling proceeds to within from 7 ft. to 24 ft, of the 
floor of the level overhead, the thickness of the arch depending upon the width of the 
lode and the character of the veinstone and of the enclosing rock. 
2*— \Vaihi-Tairim. 



20 

(c.) In places where the roof will collapse unless supported, and again where only a 
portion of the lode is being stoped and the contiguous non-payable portion is of a loose 
rubbly nature, the block is extracted on square sets, the timbers employed measuring 
about 12 in. in diameter. Filling from the surface is run in as usual from winzes. 
Occasionally the winzes sunk in the lode have been lost, and to afford fiUing-passes new 
winzes have been sunk in sohd coimtry from gangways contiguous to the foot-wall. 

{(l.) Shrinkage stoping and filling in both the Waihi and Waihi Grand Junction 
mines is practised where the wall-rock of the veins is sound, and where other conditions,- 
such as the distribution of ore-values. &c.. are favourable. The shrinkage blocks vary 
in length up to about 300 ft. They are usually worked in series, so that in some of 
them ore-breaking is completed, while in others stoping is in progress. In working this 
ore it is foimd that about 40 per cent, must be drawn off to afford convenient working- 
room in the back of the stope. One winze sunk in a median position through the 
block is usually found sufficient in this system, as far as working is concerned, the 
air-current being conducted from the level through tfie cribbed ladder-ways at each 
terminal end of the stope. Machine-drills are used, and the broken ore is .spalled to 
small size. The ore constituting the temporary filhng is always kept fairly close to the 
back of the stope. 

In this system no shovelhng is required, no cnbbing-up of passes, and no timber 
supports ; while the ore is broken for the full width up to the arched block necessary 
to support the level above. Through tliis arch winzes are sunk to admit filUng-material 
when the stope is being finally emptied. WTien emptying, the ore is drawm off from 
one end first, and the filling admitted here to take its place. The ore thus gradually 
shrinks, and the filhng advances, both on the rill.* to the other end of the stope. In 
order that the maximum amount of ore may be drawn, the waste rock packed behind 
the sets when widening the level is built up on as high an angle as possible from 
the caps to the vein-walls. A hopper-hke base to the stope is thus afforded, whereby 
the ore runs freely to the numerous passes or shoots. On very wide lodes two parallel 
drifts are required, as in the ordinary shcing and filling method. 

The shrinkage system of stoping, where favourable conditions obtain, has been found 
the most economical yet practised. 

(e.) In taking out arches, the level-timbers, three or four sets at a time, are 
temporarily supported on booms or stringers. As the ore is extracted, the sets arc 
permanently supported from stulls where the lodes do not exceed 15 ft. in width, and 
from saddle-back sets where the widths range from 15 ft. to. say, 20 ft.. In such cases 
it need hardly be stated that the supporting walls must be good. In deahng with wader 
ore-bodies, or lodes carr\-ing poor walls, the arches are taken out on square sets. \Miere 
the old level-timbers are crushed or unsound a foot- wall gangway is constructed in the 
sohd country near and parallel to the lode, and somewhat below the horizon of the 
original level. From this gangway, which is connected by quartz passes with the 
level below, the arch is attacked and timbered with square sets. This method of 
working from a secure foot-wall gangway is the safest in treacherous ground, but, as 
might be expected, cases occur when it is impracticable or uneconomical to recover even 
by this device the ore formerly left as arches. 

(/.) Open-cutting supphes all the filhng-material required for paclcing the stopes, 
excepting the relatively small amount of waste rock accruing from crosscutting and 
other developmental work. In the Waihi Mine some of these opencuts follow the strike 
of old vein outcrops, and a certain amount of ore left in the old workings is selected 
during excavation, and is trammed to the company's main surface hoppers. The 
weathered surface rock at Waihi is easily broken and handled, and packs tightly, thus 
afiording cheap and satisfactory filUng-material. The open-cutting is efiected in the 



* This term indicates that the plane limiting movement i.s a slope. 



21 

usual manner, the broken material gravitating directly through the main filHiig-passes to 
the stopes or to underground hoppers, or through minor passes into adit levels, from 
whence it is hauled in large trucks to the filling-shafts. Horses are used bv the Waihi 
Company, and electric traction by the Waihi Grand Junction Company, where haulage 
of filling is required. 

Millivc). 

Waihi milUng and cyanidation practice at the present time closely resembles that 
obtaining on other fields having similar ores, excepting in such modification of detail 
as arc due to local conditions. 

The most modern and best-arranged mill on the field is that of the Waihi Grand 
Junction Company, erected in 190(i. The metallurgical process adopted here may be 
briefly stated. 

The ore,* weighed at the mine, is conveyed to the mill by a Bleichert aerial tram, 
and initially reduced by Hadficld crushers, worked in series. Samphng is at this stage 
effected by an automatic sampler of the Vezin type. The ore. fed to the stamps 
through Challenge feeders, is there crushed in cyanide-solution of O-IO per cent, strength 
K.Cy., the proportion of solution to ore being lU : 1. Lead-acetate equal to U-5 lb. 
per ton of ore is also introduced here. The stamp-screens are of woven wire. 5, 7, 
and 10 mesh. 

From the stamps the l)ulp tiows to elevator-wheels, which raise it to the conical 
boxes, or spitzkasten. The overflow from these boxes passes to Wilfley tables, and the 
underflow, after passing through tube mills, is returned by the above-mentioned elevators 
to the spitzkasten. The Wilrtey tables are used merely as clas.sifiers, the coarser 
discharge being taken from a stretch of 18 in. along the side. This coarse material 
from the tables is raised by belt-elevators to the tube mills, and the overflow, or finer 
product, passes to a spitzlutte, the spigot product of wliich is also returned to the 
tube mills by a centrifugal pump. 

The tube-mill final product grades as follows : — p^^ (>„(. 

On l()()-me8li .. ..01 

On 150-me8h 1 •") 

On 200-mesh .. .. .. .. i;5 

Through 200-me8h .. .. .. Ull 



100-0 
It will be noted from this that ])ractically the whole of the ore is reduced to " slime," 
and it is stated that mill records have shown that 87 per cent, of the total value of 
the ore was in solution at the time of overflow from the Wilfley tables. 

The solution and shme (proportion, 10 of solution to 1 of slime) is then subjected 
in settlers to a thickening process, whereby the pulp attains a consistency of 1-5 to 1. 
Of the clear solution from the settlers 75 per cent, flows to the strong-solution sump 
and 25 per cent, to the strong-solution clarifying-tanks. The pulp, wliich is drawn 
continuously from the settlers, is pumped into storage-tanks provided with revolving arm- 
agitators, and from these it is pumped as required into tall tanks (B.M. or Pachuca 
type), where it is agitated by compressed air for a period of eighteen hours. From the 
tall tanks the pulp gravitates to a Moore basket-filter, where it receives its final treat- 
ment. The strength of cyanide-.solution is maintained altogether by additions of strong 
stock solution to that supplying the stamper-boxes. 

The zinc-filament method of precipitating the gold and silver is employed. Melting is 
done in Balback tilting furnaces, using coke fuel, and the remelting in kerosene furnaces. 

* The ore, which is unoxidizetl, consists essentially of a gangue of quartz, calcitc, and dacitic material, 
with 8 to 10 per cent, of sulphide — pyrite, sphalerite, galena, chalcopyrite, and traces of arsenic anil antimony. 



headings : {<() Rock-breaking ; (b) stamping ; (c) tube nulling ;* (d) amalgamation ou 
plates : (e) concentration on Union vanners or Wilfley tables ; (/) treatment of concen- 
trates (these amount to 1-5 per cent, of the ore) by tube milhng and cyanidatiou 
with air-agitation from eight to ten days in conical-bottom tanks worked in series ; 
(g) separation of sand and slime ; {h) cyanidation of sandf (averages 20 per cent, of 
the ore) by the percolation method, total treatment-time thirteen days : (i) treatment 
of sUrae — thickening in pointed boxes and vacuum basket-hlters, cyaniding with air- 
agitation in tall tanks for ftvc days, basket and frame vacuum washing ; (/) precipi- 
tation of the gold and silver by zinc-filament method ; (A) melting ; (/) Dore refining. 
The following hgures are submitted (year I9U9) : — 

Value of ore (average) — Gold, 9 dwt. ; silver, 3i oz. per ton. 
Residual assay (average) — -Gold, 20 gr. : silver, 17-5 dwt, per ton. 
Recovery — Gold, 91-2 per cent. ; silver, 75 per cent. 

Costs — s. (1. 

Breaking . , . , . , . . . , 5-34 

Staniping . . 10-66 

Tube mining , . . . 4-62 

Extraction . . , . , . 2 8(X) 

Power .. .. ., .. ,,0 11-38 



5 4-(X) 



Power to operate the mills is supplied l^y water, steam, and producer-gsis. .Steam- 
power costs about £18 to £20 and gas-power about £10 per b.h.p. per annum. 

At the Komata Reefs Company's mill (twenty stamps), which is the only one 
operating continuously outside the Waihi centre, the ore after passing through the 
breakers is stamped, in water, through 4-mesh screens, and is then further reduced in 
tube mills. Amalgamation on tables follows, 48-6 per cent, of the total value being 
recovered. Spitzkasten separation of the sand and sUme is followed by the cyanidation 
of each product separately, the sand by the usual percolation method, the thickened 
sHmes by air-agitation in tall tanks, followed by vacuum filtration in Moore baskets 
of the "turnover" type. Zinc-filament precipitation and the usual melting-process 
follows. An extraction of 96-6 per cent, of the total value of the ore is claimed. 

It is beyond the scope of this report to comment upon the relative merits of the 
methods of milling and treatment which have just been briefly indicated. It may, 
however, be stated that successful treatment of the ores entails very fuie grinding, 
and the degree of comminution should in ever}' case be carried to the economic limit. 

* Tlic tinal prixiuct from the tiilx- mill irraflo? — 
, HO . . 
-60+80 

- 80 -f- 100 

- 100 -h 120 
-120-1-200 

- 200 . . 

100 00 
Note. — 1,.M,.M. slamlanl ^>^■I•el■Il.s to No. 120: apirtiin- of 200-iiiesh - 072 mm. " Milling and Treat- 
ment at till- Waihi Mine, N.Z,." Banks, K. (J.. Proc. Aii.st. Inst. Min. Eng., vol. 8, No. 1, 1911. 

t The sand from the spit'ickasteii, which amounts to about 20 per cent., grades — 

Prr Cfiit, 

--60 . , . . 4:5 

-60+80 .. I-5-")" 

80+100 ..II 63 

- 100 -4^ 120 II 3:5 

- 120 ., ., 61 04 

100-00 



1'. r Cent 


002 


179 


2 62 


7 58 


8 63 


79 36 



•24 

The results of recent experiments suggest that the sUming of the whole of the ore is not 
in every case economical, but rather that the separation of the clean sands which have 
been reduced to a certain grade is the better practice. The expert cyanidation of 
every ore constitutes a separate problem, and only by continuous research in the 
laboratory, experiments in the mill, and a due regard to the improvements continually 
being effected on other fields can the best results be attained. 

FINA^•CIAL COXDITIOXS. 

The mining country of rhe Waihi-Tairua Subdivision is nearly all Crown land, or 
Native land under jurisdiction of the Crown.* 

Leases are granted by the Crown over this land for mining. These leases usually 
cover a term of forty-two years, and are subject at all times to working-regulations. 
The annual rent per acre payable by holders of mining leases is unifomi throughout 
the area — namely, 2s. 6d. for the first year, 5s. for the second year, and 7s. 6d. per 
annum thereafter. 

All the producing mines have been located by the prospector or working miner ; or, 
especially as in Waihi. where the auriferous comitry is in great part deeply buried, have 
been " staked " on the strength of discoveries in neighbouring claims. A large number 
of separately owned claims is at present in existence, but on many of these little or 
no work is being done. 

The prospector is usually initially financed by one or two of his friends, and. 
on maldng a discovery, forms a private syndicate to develop the prospect. If the find 
proves sufficiently attractive, a company is then fonned. 

The registered mining companies which at the end of 1909 held claims in the 
Waihi-Tairua Subdi%ision numbered thirty-four. Companies that have mining operations 
now in progress number eighteen. A glance at older official maps shows that a 
relatively enormous area of country has at one time or another been "' staked.'' The 
area so held was greatest during the mining " boom "' of 1895-99. but, as much 
" wild -catting," or the organizing of syndicates and companies to work worthless 
ground, was practised, the mere former existence of a lease is no criterion that a prospect 
Avas ever discovered. 

Certain mining companies, on meeting with no success, and finding themselves in 
financial difficulties, have at times resorted to the tribute system of working their 
claims. Tributes are generally granted for periods of fi'om six to twelve months. The 
royalties deducted by the companies usually amomit to 10 per cent, of the total gold 
won, over and above what will afford the tributcr half the current rate of wages. 
Although it is recorded that even the Waihi Mine and the Waitekauri Mine, when in the 
possession of the original Auckland companies, were for a time let on tribute, the system 
has never in this subdiAisiou been practised to the same extent as at Thames. While 
there is considerable justification for mine-owners occasionally resorting to the tribute 
system on the old bonanza fields of Thames and Coromandel, the same cannot be 
said of the Waihi-Tairua field. Here it is rather, to use T. A. Rickard's words, " the 
last resort of a perplexed mine-owner, and is a confession of inability to work one's 
own property."! 

Gold exported from this field, in common with the whole of the North Island 
of New Zealand, bears an export duty. This duty amounts to 2s. upon every ounce, 
troy weight, of the fineness of 20 carats and upwards. The revenue accruing 
from this gold duty reverts to the Waihi Borough Council or to the Ohinemuri 

* The Golden Belt Claim has some freehold, and the Chelmsford is on land acquired from the Kauri 
Timber Company. 

t " The Cripple Creek Goldfield,'" Proc. Inst. Jlin. and MetalL, London, 1899, p. 39. 



25 

or Thames County Council, whichever local body has jurisdiction over the area 
from which the gold is derived. The mining properties, on account of tliis special 
tax. are not assessed for local rating. 

The nominal capital of the locally organized mining conipaiues varies from £6,000 
to £150,000. divided into from 60,000 to 375,(K)0 shares of a par value of from 2s. 
to £1. Frequently very little regard is paid to the size or prospective value of a 
claim in fixing the nominal capitahzation of the company formed to work it. and in 
many cases this capitahzation is imaginary rather than real. Most of these companies 
are in reality prospecting rather than mining companies: and of the twenty-two local 
companies now listed on the Auckland Stock Exchange, only one — the Tairua Broken 
Hills — has yielded the value of its capitahzation in dividends. The working capital of 
nearly all these companies has been subscribed in Auckland, and the province of which 
it is the diief commercial centre, but during recent years capital is being drawn from 
southern parts of the Dominion. 

Companies now in operation, which have been organized in London. nunil)er three. 
These are — (1.) The Waihi Gold-mining Company (Limited) : Capital. 5(K).000 shares at 
£1 ; output to end of year 1910. £9.106.318; dividends. £4.251,554. (2.) The Waihi 
(Jrand Junction (Jold Company (Limited) : Capital. 400. (KM) shares at £1 ; output to 
end of 1910, £387.772 ; dividends. £19,218. (3.) Komata Reefs Gold-mining Company : 
Capital. 8(K).0(K) shares at 5s. : output to end of 1910, £369,017 ; dividends. £33,333. Li 
addition to these, the .Jubilee Claim, at Waitekauri. has for some years been inter- 
mittently worked by a London syndicate ; while certain claims at Waihi — the Ronuilus 
;^roup — are being initially prospected with the diamond-drill by a small English company. 

In the past, over a dozen other companies.* financed in England. ha\e at one 
tijne or another ventured into Hauraki mining. Of these, the Waitekauri (iold- 
mining Company has the best record, having produced bullion valued at £309.769. and 
paid dividends totalling £84.035. Of the other companies, six were bullion-])ioducers. 
but paid no dividends ; the remainder did not raise an ounce of gold, and in some 
cases were but mere squanderers of British sovereigns. 

English investors in mines of the Waihi-Tairua .Sui)division. while they have 
drawn many blanks, have, on the whole, reaped fair profits. Of a total gold-production 
of £10,824,304, up to the end of 1910. no less than £10.(X)5,070 is accredited to mines 
owned by English companies. 

It always proves a difficult matter to raise a relatively large amount of capital in 
New 2^aland to exploit a big prospecting proposition or to develop a mine, and 
recouree is usually had to London. There is, however, a disposition on the part of 
New Zealand investors to buy back through the stock market, even at enhanced prices, 
local mines developed or being developed successfully by Enghsh capital. 

The value of a mine is generally measured by the price of the proprietary comp<iny's 
shares. The appraisal, however, of mining properties in Hauraki, as on many other helds, 
particularly of properties wliich rank only as prospecting propositions, is admittedly 
a difficult problem. Even in regard to producing-mines with developmental work 
fiiirly well advanced, there is a constant tendency towards inflation of values, which 
eventually results not only in disaster to investors, but in a shaking of confidence in 
the industry. The year just closed has afforded a particularly striking example of 
this. The market valuation (£5,(J<X),000) placed upon the Waihi Mine at the beginning 
of 1910 assessed the life of the mine at nineteen years, calculated on a 6-per-cent. 
basis, the declared ore-reserve at this time being equal to Uttle more than a three-years 

* Whangainata (iold Corporation (Limited); Hauraki Peniii.suia f'>.\i>loiatioii Company; Hikutaia 
Cold .Syndicatt': Royal Stantlard, Manaiiu, Waitekauri, VV'aitekauri E.xtciided, Waitekauri Cross, Waite- 
kauri Union, Union- Waihi, Waihi-Silverton, and Fa vona- Brilliant gold- mining companies. 



26 

iiiill-su2)ply. The excessive prospective value placed upon these shares naturally vanished 
when disappointing results attended recent low-level developmental work. This is only a 
repetition of what occurred nine years previously in connection with the Golden Cross 
Mine, Waitekauri, then the property of the Waitekauri Gold-mining Company, London. 

The cost of prospecting and developing claims in nearly all of the smaller mining 
camps of the area under review is high, and the same has proved true in respect 
to the developmental work of earher years in the larger camps. Although the physical 
configuration of the greater part of the country, with its deeply incised valleys, is 
favourable to cheap mining, it has its disadvantages. It frequently involves an 
isolation of prospects. This increases the cost of getting machinery and supplies on 
the ground, and of sending for treatment bulk parcels of ore to the nearest mill 
should the prospects at the earher stages of development not warrant the erection 
of a treatment plant. This is the prime reason for the failure of customs mills on 
this field, and also in part accounts for the large amount of money spent in erecting 
small batteries, which have in many cases never even crushed sufficient ore to cover 
the cost of their erection. 

Figures covering the total cost of mining and general expenses ajjpear only in 
the reports of the Waihi, the Waihi Grand Junction, and the Komata Reefs companies. 
For the year ending 1910 these companies' costs amoimted respectively to 17s. lid.. 
£1 is. 5-ld..* and £1 15s. 7d. per ton of 2,0001b.. wliich, considering the tonnage, the 
character of the ores, and the local conditions, may. on the whole, be considered 
satisfactory. Each year, moreover, is showing a gradual reduction of mining and 
milhng costs, follo^^^ng the introduction of improved methods and apphances. 

The minimum rate of wages on the Waihi field, in common with the whole 
Hauraki goldfields, is at the present time fixed by an Arbitration Court award. t This 
scale is as follows : Ordinary miners, 8s. 6d. per diem of eight hours ; machine-men, 
9s. per diem of eight hours ; shaft hands, 9s. for six hours ; engine-drivers, 10s. for eight 
hours ; battery hands, 8s. 6d. (an average) of eight hours. 

The number of men employed in the Waihi-Tairua Subdivision during 1909 
averaged 2,250. and of those 1,924 were on the pay-rolls of the Waihi and Waihi 
Grand Junction companies. 

In the larger mines the wages system has been found unsatisfactory, and all 
sinking, driving, rising, and stoping is now done on contract. The contracts are 
usually taken by parties of miners. Any wages-men employed by these contractors are 
paid on the average about 3s. per day in excess of the award rate. There can, 
however, be no question but that the worldng miner, as a contractor, gets quid pro quo 
out of his employees. 

In the past the conditions of labour have, on the whole, been fairly satisfactory, 
although at Wailii minor disputes have at times occurred, and strikes have been 
narrow'ly averted. With fair wages, an equable and healthy chmate, and a relatively 
low cost of hving, there w'ould seem to be httle ground for serious labour troubles ; 
yet one can hardly be sanguine as to what the future may bring forth. 

In Tairua and the other outlying camps the labour position is not satisfactory, 
as th^re seems to be an aversion on the part of capable miners, mill-men, and artisans 
to live outside the more accessible and larger centres of population, where their services 
are in almost constant demand. Mining-costs in these particular camps are, for this 
reason, too high. The construction of the coach-road, which is already surveyed, to 
connect Tairua with the Thames via the Kauaeranga will considerably ease the present 
unsatisfactory position. 



* The actual cost of mining and milling (not including mine-development) at the Waihi Grand Junction 
Mine for the year 1910 was 15s. 3d. per ton. 

t As far as Waihi is concerned, this award has been (prior to June, 1011) abandoned. 



'21 



CHAPTER 111. 
PHYSIOGRAPHY. 

Page Pag» 

Introiluction . . . . 27 The Shore-liiif . . 30 

The Land . . .28 U^amage-challneJ^ . . 32 

(1.) Flats.. .. ..28 Swamps ..32 

(2.) Plateaux . . . . .2!) Springs . . 33 

(3.) Peaks and Hidges ..29 Man's IiiHuemc mi tlie I'hysical Features 34 

IXTROmCTION. 

Thk Uiud-surfiice of tlic Waihi-Taiiua Subdivision consists almost entirely of a volcanic 
mass of medium elevation. This land-mass, after its dissection had proceeded to an 
advanced stage, was considerably dopresscd.* Recently it has been elevated to a very 
much lesser degree. Thus has been ' produced a deeply indented shore-line complex in 
origin, on wliich littoral agencies have already made marked changes. 

If the recent sands and gravels and a few inter-fonuational beds of conglomeiate be 
excepted, the rocks of the subdivision, as previously mentioned, consist altogether of 
Tertiary volcanics. These volcanics belong to three groups — namely, (1) andesitic and 
dacitic lavas and breccias of the '" Fii"st Period '" : (2) andesitic and dacitic lavas and 
breccias of the '" Second Period " ; and (:}) rhyolitic lavas and breccias of the " Third 
Period." 

In general, the lavas, unless highly altered, are much more resistant to weathering- 
agencies than are the fragmentals;. Lavas predominate in the first group, and probably 
also in the second, l)ut in the third they cover a less area than the breccias. The 
rhyoUtic breccias and tufts, whiih are of widespread occunence, withstand atmospheric 
attack better than might be expected of rocks of only moderate consolidation. Where 
silicitied, these fragmentals often become as durable as the associated lavas. 

The irregular distribution of the several formations which has so pronouncedly 
mfluonced the character of the topography is easily luiderstood when one considers the 
various cycles througli which the land has passed. On a submaturely dissected surface 
of Jurassic and pre-Jurassic sedimentaries (not exposed in the subdiN-ision under review, 
but visible in those to the north and west) were extruded in early Tertiary times the 
great thicknesses of the " First Period " volcanics. Then supervened a stage of com- 
parative quiescence, during which the newly deposited lavas and breccias were carved into 
liill and valley by stream erosion, and on the irregular surface vegetation grew, which 
has afforded thin coaly seams. Again, the area became the scene of great eruptive 
activity, and the volcanics of the " Second Period " were widely outpoured and ejected, 
resulting in a marked alteration in the contiguration of the land. Once more during a 
period of comparative tranquihty the dissection of the land advanced, new valleys were 
eroded, old ones were further excavated, and there flourished in places the forests which 
have yielded seams of impure coal. \'olcanic activity, however, was yet again to 
manifest itself on a grand scale, and over wide areas. Rocks more acidic than those of 
the earher eruptions — rhyohtes — were extruded. Again, valleys were filled, plains of 
limited extent fonned, and the direction of the drainage in many places markedly 
changed. Subsequent to this last great period of volcanic activity andesitic dykes were 



* It seems probable that the moTement of depression was a long-continued one, and was going on 
contemporaneously with dissection. 



28 

intruded in various places, and lavas-' even flowed out on the surface, in places protecting 
from denudation the softer intruded rocks. Faulting has occurred within the volcanic 
complex from time to time, and this in sonu' places may have had an influence on the 
character of the topography. Since the close of the last period of volcanic activity 
denudation has, on account of the moist climate, proceeded fairly rapidly. Everywhere 
the surface has been deeply dissected to an advanced degree, and, where the softer of the 
fragmental volcanics occur, even to a mature stage. 

Regional earth-movements effecting the depression of the south-easteni portion of 
Hauraki appear to have been more or less continuous since earUer Tertiary times. In 
later PUocene times, however, after considerable sculpturing of the rhyohtes had been 
effected, the movement was evidently greatly accentuated, and the sea encroached 
relatively long distances on the land, thus markedly altering the character of the strand- 
line. Since this depression the shore-line has undergone certain changes — the bays and 
estuaries have been ^\^dely insilted. and the intervening promontories abruptly truncated. 
In recent times a very moderate elevation took place, at least in the southern part of 
the subdivision, the visible effects of this movement being rather local. 

The Land. 

If the land-surface of the Waihi-Tairua Subdivision be viewed from any suitable 
vantage-point, the absence of order exliibited in the maze of low peaks and rolhng 
ridges spread out in all directions towards the horizon is at once apparent. Here and 
there, however, may be observed plateaux of var^'ing altitudes, in some places little 
dissected, in others represented only by flat-topped ridges. Along the lower courses of 
the larger streams low-lpng and often swampy flood-plains are to be seen, which widen 
towards the sea, and there merge into the flats formed by the deposition of sand and silt 
in the inlets. 

The land -surface may be described mider the following headings : (1.) Flats due to 
fluviatile deposition, aided in places by marine sedimentation. (2.) Plateaux formed by 
the deposition of " Third Period " rhyohtic ejecta in depressions or valleys in older rocks. 
(3.) Peaks and ridges representing, in part, the dissected older volcanic mass which ante- 
dated the " Third Period " of vulcauism ; in part, the rhyohtic necks of the " Third 
Period " ; in part, the audesitic dykes of even more recent origin. 

(1.) Flats. 

Low-lying flats occupy only a very small portion of the land-surface of the sub- 
division. They occur at the mouths and lower reaches of nearly all the larger streams 
flowing to the eastern seaboard, and of those entering the broad Thames Valley on the 
west. 

The alluvial flats are everywhere relatively long and narrow. Though in general 
they diminish in size as a valley is ascended, they widen considerably in softer rocks, 
and contract or disappear altogether where hard rocks are intersected. This is particularly 
noticeable on ascending the Tairua Valley, where relatively broad flats mark the lower 
reaches of the river as far as Broken Hills. Here a gorge intervenes, and is followed again 
by flats extending to the second gorge at Quartz Creek. Allu\-ial flats are also conspicuous 
along the lower Wharekawa and AVhenuakite on the eastern side, and along the Puiiri, 
Omahu, Hikutaia, and Ohinemuri on the western watershed. 

All of the large streams on the eastern side of the watershed enter coastal inlets, in 
the sheltered waters of which mangrove swamps are conspicuous, and materially aid in 
promoting sedimentation of stream-debris. The area of low-lying land close to the sea is 
also being constantly augmented by the spread of the sand blown inland from the open 



I'l.ATK VI. 







^'IE\V l.dilKIXi. AoUTH-KA^T ABUVK JlXCTIdX UF lllKL'TAIA AND W A [I'AHEKK St1;KA-M.-> 




t<r4<^ 



•-iv,.- ■:^- 



^^.■...,m 



isi ■■■■> z"*^ 






•;^X4^-----^!>: 



liJlYULITE PiXNACLE, MaISATUTO. 



Face p. 1^9.-} 



29 

oceaii-beach. Of this nature arc tho oxtensive sandy flats, devastated by sand-dunes. 
lying between WTiareka\va and Ohui. and between the entrance of Whangamata Harbour 
and Otahu Inlet. 

The fairly large flat extending southward from Waihi Beach headlands, and tho much 
smaller flat at Orokawa Bay, represent areas of marine sedimentation only recently 
elevated above the sea. Orokawa Beach, with its crescent of yellowish-white sand, flanked 
by rocky cliffs at either end, and bordered by a forest of tall poluitukawa trees, forms a 
picturesque feature. Four distinct terraces are here visible, each of which shows a former 
position of the strand. 

Terraces bordering the streams in the interior along the alhiyial flats are not common 
features, but they occur on the Waitekauri, Whenuakite, and elsewhere. 

(2.) The Plateaux. 

The ])lateaux of volcanic origin fonnerly occupied by far tin- greater part of the sub- 
dixHsion, a fact testified by the widespread occurrence of i.solated nuvsses of horizontally 
stratified or gently inclined rhyolitic nuit^'rial lying in valleys, and forming benches on high 
peaks composed nuiinly of older rocks. Now, however, only a snuill proportion of these 
plateaux preserve a semblance of their original character. 

The most extensive of these features, remaining in great part intact, forms what is 
generally known as the Waihi Plain. This, however, lies mostly beyond the southern 
limits of the subdivision. In area it measures about seven miles by four. Its surface 
is gently undulating, and has a general elevation of from 250 ft. to 350 ft. The sugges- 
tion has frequently been made that this plain represents an old tufa and lava filled 
lake-basin, and from the available evidence this assumption may be correct. At any 
rate, an extensive depression, which was apparently at the headwaters of a large stream 
flowing towards the eastern seaboard, formerly existed here. The plateau is now 
drained mainly by the Ohinemuri, which flows westward through the rock-girt Karanga- 
hake Gorge to the valley of the Thames. 

At " The Wires," near the headwaters of the Tairua, hcs at an altitude of some 
1,500 ft. a plateau about two miles in its greatest dimension. It seems probable 
that this volcanic feature formerly extended far down the valley of what is now the 
Hikutaia Stream, and that the rapid descent of the drainage-channels to the low-lying 
Thames Valley on the west resulted in its speedy degradation. Scarcely a trace of it 
is now visible in the Hikutaia Valley, except at the actual headwaters. 

The country extending from the lower Wharekawa, northward to and beyond the 
limits of the subdi\'ision and westward to the headwaters of the Hilii and the western 
tributaries of the Tairua, contains many well-preserved remnants of once extensive 
plateaux. 

It is unlikely that the various volcanic plateaux ever fonned one continuous feature 
having a luiiform elevation. Uniformity in height would scarcely be expected, owing 
to the great niunber of foci of rhyolitic eruption. Faulting since formation of the 
plateaux may in part account for variance in altitude. Much of this elevated but 
greatly dissected flat country stands at altitudes of between 1,500 ft. and 2,000 ft. 

(3.) Peaks and Jtidges. 

Before the rhyolitic lavas and pyroclastics of the " Third Period " had been 

deposited, the land-surface, as before remarked, had been deeply dissected, with the 

consequent formation of well-defined ranges, ridges, and spurs. Parts of this old 

surface were never covered by the rhyohtic material, and large portions, again, have 



30 

been denuded of it. Wherever the " First " and " Second " period volcanics occur the 
topography of the area is usually characterized by well-graded slopes, not infrequently 
exhibiting steep angles towards the higher crests, and more gradual inclinations at lower 
altitudes. There is also a marked absence of rock-outcrops, except on the banks of 
streams and on prominent peaks. Typically of this nature is the topography exhibited 
by a great part of the country draining to the Thames Valley. 

In general, a more rugged topography than that shown by the " First " and 
" Second " periods of volcanics is exhibited by the rhyolitic plugs and dissected flows 
which are conspicuous in various parts of the subdivision. Though in many places these 
show to their summits graded slopes practically free from rock-ledges, more commonly 
scarps and broken crags appear at the higher elevations. 

The imposing range of hills with serrate sky-hne seen to the north-westward of 
the lower Tairua Valley exhibits to a marked degree the more rugged phase of the 
rhyohtic topography. Again, the maze of rocky rhyohtic hills surrounding the fan-hke 
basin at the head of the Waipaheke (Maratoto) suggests the modified aiguille topo- 
graphy seen in the non-glaciated portions of regions which have recently been markedly 
influenced by ice-action. 

The rhyohtic hills to the eastward of Waihi usually exhibit gentle slopes to the 
lower ground of the plains, but the descent to the strand-hne is here, as elsewhere along 
the coast, abrupt, and many almost vertical dechvities occur. 

The recent andesitic dyke rocks have modified only in a few places the topography 
of the area under review. The long flat crest of Table Mountain (2,600 ft.) is due to the 
intrusion of a great dyke of andesite into softer rocks. This mountain forms one of the 
most conspicuous features of the landscape, being \nsible from almost every vantage-point 
in the subdivision. A portion of the plateau country lying north-west of the lower 
Wharekawa also owes its preservation in part to andesitic intrusions protecting the 
softer tufaceous rhyolites. 

The Shore-line. 

The eastern border of the subdivision for a distance of thirty-eight miles, as the 
crow flies, is formed by the open Pacific Ocean. Numerous indentations stretch inland, 
giving altogether a shore-Une of about eighty miles. 

The coast-line here bears a striking resemblance in its main characteristics to that of 
other portions of the Hauraki Peninsula (described in Bulletins Nos. 4 and 10), and also 
to that of the Whangaroa Subdi\'ision (discussed in Bulletin No. 8). It forms a good 
example of the efiect produced by a general depression of a land-surface which exhibited 
for the most part a subdued topography and a well-developed drainage-system. The 
deeply indented coast ; the sunken stream-mouths ; the numerous rocky islands, stacks, 
and skerries bordering the strand ; the mari)ie-cut caves and rocky chasms into which 
the water rushes at every stage of the tide : ail testify to the youthfulness of the shore- 
line. However, change from the initial outhne is shown by the steep cliffs cut in the 
headlands between the streams, by the silting of the bay-heads aided by the advance 
of mangrove swamps, and by the formation of extensive barrier-beaches across the 
mouths of the inlets. A slight elevation of the strand-line since depression, and 
apparently a very recent movement, is shown at the south-eastern corner of the sub- 
division by the elevated beaches (the highest about 50 ft.) of Waihi Beach and Orokawa 
Bay, and by a well-cut rock-shelf and sea-worn caves on the north side of the bay 
named. 




... 05 



31 

By far the oreater part of the coast-line of the subdivision is occupied by bold 
rocky headlands, but these are varied by sandy beaches, and less frequentlv by gravel 
or shingle beaches. These beaches may extend for three or four miles, as in the case of 
the ^\^lareka\va-^Vhangamata and Waihi beaches, but in most cases are much shorter. 
The headlands nearly everywhere descend steeply to the water's edge. Where rhyoUtic 
lavas occupy the coast-line, as is fre(|uently the case, the descent is often especiallv 
abrupt, cliil's up to 2(X) ft. or 3(K) ft. in height tnincating the well-graded slopes leading 
from the interior. Even where andesites and the less resistant of the rhvolitic breccias 
occur moderate clifls, as a rule, face the ocean. 

Judging by the soundings given on the Admiralty chart, and by tlie numerous 
islands which dot the ocean close to the shore, it may be assumed that the island shelf 
extends for miles eastward, and that an elevation of only a few hundred feet would very 
greatly increase the land-surface of this portion of New Zealand. 

The shore-line is broken by numerous shallow bays and rock-girt coves, while 
four inlets stretch some distance into the interior. These four inlets — Tairua. Whare- 
kawa, Whangamata, and Otahu — afford shelter for such small craft as can cross the 
bars at their mouths. Whangamata Harbour and Tairua Harboiir alone are at present 
visited by vessels which trade from Auckland down the coast. 

Tairua Harbour, though bordered by steep slopes near the entrance, is in its upper 
reaches surrounded by broad marshy flat.s. fringed by mangrove swamps. The harbour 
and river are navigable for sn\all oil-launches as far as Hikuwai, a distanc-e of about 
seven miles from the open sea. The harbour-entrance is protected by the land-tied Paku 
Island. 

WHiarekawa Harbour closely resembles Tairua Harbour, though its shores are in 
general less swampy, and the bordering land higher. It was formerly a much more 
spacious embayment, extending as far north as Ohui. However, the southward advance 
of a broad barrier-beach, behind which tlie existence of extensive salt marshes indicate 
a former lagoon, has greatly diminished its area. 

Whangamata Harbour and Otahu Inlet, now separated by a t)road sandy flat, 
formed originally one feature. Kach closely resembles the inlets already described. 
A bold foreland se])arates the upper part of Whangamata Harljour from the open sea, 
while low rolling hills and. less frequently, grassy Hats bordci it to the westward. 

Within the northern ])art of the area under review lies the southern portion of 
Whitianga Harbour. It exhibit.s the same wide mangrove swamps, bordered l)y marsh v 
low-lying lands, as do the upper reaches of the other inlets mentioned. 

Numerous streams enter all the embaynu-nts of the coast-line, and in places several 
entering-streams represent the dismembered drainage of the same parent stream. The 
creeks entering rocky coves not infrequently discharge into the sea over a waterfall, 
having been betrunked by cliff-retreat. 

Sand-dunes are conspicuous along the jjrominent l)arrier-beaches flanking the entrance 
to all the larger inlete. 

Rock-benches are less common along the portion of the shore-line being described 
than in the northern part of the Hauraki Peninsula. Skerries, stacks, and small rocky 
islets, however, are often to be seen along the shore-line in the vicinity of the headlands. 

Numerous fairly large islands lie close to the shore of the mainland. Among others 
may be mentioned the Shoe Island group and the Slipper Island group. The islands 
of each group exhibit outlines of nuld relief, broken by coastal declivities. The Alderman 
Islands, which are situated some thirteen miles ofT the coast, form a group of pecuUarly 
shaped rugged pinnacles and rocky hummocks rising from the island shelf. At WTianga- 
mata shallow water intervenes between the mainland and the craggy islands lying a 
short; distance off the shore, and at very low tides they are practically land-tied. 



82 

Drainage-channels. 

In a previous paragraph it was mentioned that the land within the Waihi-Tairua 
Subdivision had been submaturely dissectt'd prior to the last depression. As may be 
expected, the dissection was more mature where the softer of the volcanics occur than 
where the harder andesites and rhyolites appear. With the depression of the land the 
lower parts of the valleys were drowned, the streams dismembered, and other changes, 
which have been described in previous paragraphs, resulted. 

The general system of drainage is that which may be expected in an elevated mass 
of volcanic rocks diverse in character and compUcated in structure. The stream-channels 
everywhere ramify irregularly, and the branching is intricate, complex, and fan-like. 
The valleys, almost to their heads, are deeply cut, and the local relief is consequently 
nearly everywhere great. As the hinterland is still widely forested, the streams retain 
thpir volume of pure fresh water, derived from a copious rainfall, to a degree which would 
be considered remarkable in lands less favoured than New Zealand. All the larg(>r 
streams flow at grade in their lower and middle courses, and even the small'^r channels 
are graded for a long distance from their mouths, except in places where on entering 
the sea a waterfall occurs — due to cUf?-retreat. In their upper reaches many of the 
streams are partly graded, except at their heads, where waterfalls are nearly always 
seen. Thus the Tairua, which is the longest stream in the subdivision — namely, thirty- 
one miles, following its numerous ramifications — is graded practically all the way to the 
mouth of Collins Creek, a distance of about fifteen miles. Above this for five or six 
miles its course rises rapidly, series of waterfalls over hard andesites alternating with 
occasional stretches of cahner water. Still farther up, near " The Wires " plateau, the 
stream flows in well-graded broad meanders, but beyond this again its waters descend in 
a series of waterfalls from the bush-clad slopes of Ngapuketurua and Hikurangi. 

It seems probable that the headwaters of the Tairua will eventually be captured by 
a headwater tributary of the Hikutaia Stream — Huia Creek, which descends very 
rapidly for a few miles, and is then graded, or almost graded, to its mouth. 

The Ohinouuri, which is the second largest stream of the area, meanders at grade 
across the Waihi Plain ; in fact, some of its tributaries, notably the Homunga, are 
swampy even at their headwaters. In the Karangahake Gorge, however, where the 
stream flows between lofty buttresses, its course is broken by rapids for about half a 
mile. Below this the fall gradually diminishes, and the stream meanders to its junction 
with the Thames (or Waihou) River at Paeroa, the latter river being tidal even above this 
junction. 

It is thought that the ancient Ohinemuri flowed to the eastern and not to the 
western coast-hne. This reversal of drainage appears to have been due to the ponding 
of the river-valley by the extiiisions of rhyolite in the vicinity of the eastern coast-hne. 

The Billy-goat Creek, one of the upper tributaries of the Kauaeranga, which lies 
within the subdivision, is graded in its lower course — through andesite — and again in its 
middle course across a tableland of rhyoUtic breccias. Between, the two, however, 
a magnificent waterfall of 500 ft. intervenes, where a hard rib of massive rhyohte has 
protected the softer tufaceous rocks. 

SWAJIP-S. 

Swamps are common features throughout the subdivision. As a rule, they are not 
large, and it is noteworthy that they are more common in open or partly cleared 
comitry than in forest-clad portions. The thick growth of raupo {Tyfha augustifolia) 
which covers them in so many places forms patches of ^^\'id green against the sombre 
hues of manuka and other scrub. 




I'l.AlE ^lll. \\ Al hl;t-.\i.l..- i.N Ullil ( l(Kl.K, A lltllllTAUV 



111- liu; KaL AKltANOA. 



Face p. 3^.] 



33 

The lower reaches of nearly all the large streams, and of many of the smaller ones, 
are in places swampy. Many of these swamps, especially in the Thames Valley, have 
afforded, on being drained, broad areas of fertile land, whilst whore complete drainage 
was not possible the cultivation of the native flax (Phmmium tenax) has been under- 
taken with success. 

Mangrove swamps — stretches of tidal mud - flat upon which mangroves flourish — are 
found at the he:«l of all the large inlets of the eastern coast-line. 



Springs. 

Fresh -water springs of appreciable volume are not conmion in the subdi\asion, but 
minor seepages from the hill-sides occur nearly everywhere, especially in the higher 
countr}'. Certain of these seepages carry chalybeate waters. 

Near the settlement of Puriri, and just beyond the western boundarv of the sub- 
division, issues from low-lying country the spring from which is obtained the well-known 
Puriri mineral water. The flow of the spring varies with the rainfall. During the past 
summer, which was a dry season, the flow amounted to about 432 gallons every twenty- 
four hours. It issues at a temperature of 62° Fahr. The water is shipped in casks to 
Auckland, where it is aerated and bottled by the proprietary firm, the Campbell anil 
Ehrenfried Company (Limited.) The analysis of the water as given on the company's labels 
is as follows* : — 

Grains per (iallini. 
Bicarbonate of soda . . . . 452-393 

lime . . . . . . . . 28-50(; 

,, magnesia . . . . 25-625 

Sulphate of potash .. .. .. .. 4-93^< 

soda . . . . . . . . . . . . 0-940 

SiUca . . . . . . . . . . . . 2-772 

Chloride of sodium 21-938 



Iodide of magnesium and phosphate of soda 



Traces. 



537-112 

Only one hot spring is known to exist in the area. One of the writers has else- 
where described thie — the Onia Hot Spring. It issues on the sea-beach, between high 
and low tide marks, near the mouth of the Taiwawe River, at the extreme north-eastern 
comer of the subdivision. The spring is believed to issue from a deep-seated fissure 
near the contact of andesitic and rhyolitic rocks. An analysis of the water, together 
with the remarks of the Dominion Analyst thereon, f may be quoted : — 

GrainH per Gallon. 
Potassium-chloride . . . . 7-2 



Sodium-chloride 

Calcium-bicarbonate 

Calcium-chloride 

Magnesium-chloride 

Silica 



200-8 

22-5 

21-6 

1-8 

5-5 



Total 



259-4 



* For original analysis of this water (bj- Skey) see Ann. Rep. Col. Mus. and Lab.. No. 8, 187.3, p. 20, 
and Trans., vol. 10, 1877, p. 426. .See also l^h. Rep., No. 1.5, 1880, p. 45; and " Data of Geochemistry," 
by F. W. Clarke (U.S. G.S.), 1st c-dition, 1908. p. 148 : 2nd edition, 1911, p. 1»0. 

t Sff Bull- ^'o- 4. ^'-Z. G.S. (New Series), p. .38. 



3 — Waihi-Tairua. 



34 

" The water belongs to the class of muriated sahne waters found at Kawhia, 
Gisbome, &c. 

" Most of the hot springs of this class in New Zealand contain iodine, but none 
could be detected in this water in the small amount available for the test." 

Man's Influence on the Physical Features. 

The fortification trenches and terraces cut by the Maoris of fonner days on almost 
every prominent or isolated hill near the sea-coast give a curious step-hke effect to 
many a slope and crest, but the modification of the natural configuration is, of course, 
geologically insignificant. 

As tbe subdi\'ision has for many years been an extensive timber - producer, the 
" dri\'ing " of the large kauri-logs in the creeks by " tripping " dams during flood-time 
has had a marked effect on many of the watercourses. The softer debris at the angles 
in the stream-beds has been torn away, comers of harder rocks have been broken off, 
and the courses of the streams have been widened. The lumberman, furthermore, resorts 
to wholesale blasting operations in order to pro\ade a smoother course for the passage 
of the logs. In places even new channels have been formed, and arable allu%'ial land 
devastated. 

Mining operations have had some shght effect in modifpng surface-configuration. 
At Martha Hill, Waihi, in particular, where extensive open-cutting is done, the contour 
of the land locally is considerably altered. 



35 



CHAPTER IV. 



Outline of Main Geological Features 
Table of Formations . . 
Pre-Jurassic and Jurassic Stratified Rocks 
Igneous Rocks 

(1.) Tertiary Volcanic Rocks of the 
" First Period " 
General Statement 
Age 

Distribution.. 
Petrology 
(2.) Tertiary Volcanic Rocks of the 
" Second Period " (Beeson's 
Island Series) 
General Statement 
Age and Correlation . . 

(a.) Older Group of Beeson's 
Island Series 
Distribution . . 
Structure and Petrology 



ERAL GEOLOGY. 


Page 






35 


Igneous Hocks — continited. 


37 


(2.) 


Tertiary \'olcanic Rocks, &c. — 


38 




contitiued. 


39 




Ago and Correlation — cotitiniird. 
(b.) Younger (Jroup of Beeson's 


39 




Island Series 


39 




Distribution. . 


39 




Structure and Petrology 


39 


(3.) 


Tertiary Volcanic Rocks of the 


40 




" Third Period " . . 
General Statement 
Age 


43 




Distribution . . 


43 




Structure and Petrology 


43 


(4.) 


Intrusive Rocks of \'arious Periods 
General Statement 


44 




Distribution and Petrology 


44 


Pleistocene and Recent Deposits 


44 


Regional Earth-movements and Faulting 



Pa (re 



45 
45 
45 

46 
46 
46 
46 
47 
49 
49 
49 
49 
50 



Outline of Main Geological Features. 

The oldest rocks which can be inferred to exist in the Waihi-Tairua Subdivision, 
although not visible at the surface, nor yet in the deepest mine-workings, are folded 
strata of Jurassic or pre-Jurassic age.* The accompanying sketch shows approximately 
the distribution of these — the " basement rocks " of the Hauniki mining division — with 
respect to the area now under review. 




* These rocks are described in BulL No. 4 and Bull. No. 10 (New Series) of the New Zealand Geological 
Survey. 

3 •—Waihi-Tairua. 



36 

The buriod old land -surface of these sedimentary rocks is evidently markedly 
irregular, and. furthermore, the strata have been intruded in many places by igneous 
rooks. It is difficult even to guess as to where or at what depth in any given locaUty 
the basement rocks exist. 

A great complex of volcanic rocks has been extruded through, and rests upon, the 
depressed basement sedimentaries, and, with the exception of recent fluviatile and littoral 
deposits, constitutes the whole rock-mass of the subdivision. 

The volcanics consist of andesitic, dacitic, and rhyolitic lava-flows, vath their asso- 
ciated tuf?s and breccias, and are in totn of Tertiary age. They form mountainous 
country, in places exceeding 2,500 ft. in height, and, again, persist beyond a proven depth 
of 800 ft. below sea-level. The stupendous volcanic activity which gave birth to this 
great pile of tuffs, breccias, and lavas first manifested itself in early Tertiary times, and, 
with certain periods of intermission, continued until Phocene times, if not later. Its 
initiation was probably related to the ^\^despread orogenic movements which resulted in 
the upUft of the principal Ncav Zealand coal-bearing strata. 

As described in the physiographic section, the area is deeply dissected by fluviatile 
agencies, and the usual land-forms characteristic of original volcanic accumulation — such as 
symmetrical cones, explosion craters, and fissures — have, even in rocks of the younger 
series, been entirely obhterated. 

The subdivision of the rocks of the volcanic complex according to age is one of the 
most difficult problems connected vnth. the geology of Hauraki. Rocks belonging to 
three different periods of eruption are with certainty recognizable. Again, rocks exist 
which have a recognizable position in the sequence, but which present great difficulty 
in their reference to one particular period or to another. The position leaves room for 
considerable divergence of opinion in regard to mapping, but there seems to be insuffi- 
cient evidence to estabhsh the existence of more than the three main periods of eruptive 
activity. 

Following the group nomenclature adopted in the report on the adjoining Coro- 
mandel and Thames subdivisions, the volcanics of the three groups in the Waihi- 
Tairua area have been designated the Tertiary volcanics of the " First," " Second," 
and " Tliird " periods respectively. 

The " First Period " volcanics consist almost entirely of andesitic and dacitic rocks, 
rhyoUtes, or at least dacite-rhyohtes, being confined to one small patch in the area. The 
tuffs and breccias are well consoHdated, and, together with the lavas, have in general 
been considerably altered by hydrothermal action. 

The " Second Period " volcanics, or the Beeson's Island Series, which in this sub- 
division appear to be divisible into a lower and an upper group, were extruded on a very 
irregularly eroded surface of the older volcanics. They consist of andesitic tuffs, breccias 
and agglomerates, and lavas ; the fragmentals, particularly those of the upper horizons, 
lacking the consoUdation of the fragmentals of the " First Period." Dark-coloured 
carbonaceous mudstones, coaly partings, and even seams of lignite mark in places the 
imconformity at the base of this series, or, again, mark pauses between the successive 
eruptions of this period. 

The " Third Period " volcanics, the most recent extrusives, are rhyoHtic and dacitic 
tuffs, breccias, and lavas. These rocks have a particularly widespread development 
both at the higher and lower elevations, although in many places mere residuals of 
former extensive rhyoUtic plateaux have survived erosion. 

Intrusive rocks in the form of dykes are not uncommon, but owing to the general 
similarity in mineralogical character between the intrusive and the intruded rocks they 
are often difficult to separate. One of the most conspicuous features, however, of the 



37 

whole Hiiuraki landscape is a great (Table Mountain) dyke of liyperstlienc-audesite which 
breaks through the Pliocene rhyolites. Numerous small dykes are probably referable to 
this — the last — manifestation of volcanic activity in Hauraki. 

Mapping of the several series of volcanic rocks reveals a very patchy structure, as 
might be expected from the extensive erosion that was effected between the several 
periods of volcanic activity, together Avith the degradation of the land-surface Avhich lias 
been effected since the final cessation of vulcanism. 

The profound alteration of extensive belts of all three scries of volcanics is a con- 
spicuous feature of the area under review. These altered rocks in many locaUties exhibit 
extensive cappings of siliceous sinter, or are intersected by mineral veins, certain of which 
enclose the ore-deposits that give to the subdivision its economic importance. All these 
are evidences of former periods of great hydrothermal activity — eruptive " after-actions " 
that have marked the dN-ing stages of vulcanism. WTiile alteration of the rocks and 
the occurrence of mineral veins is relatively widespread,. areas of metallization of commer- 
cial importance are circumscribed, and appear to have been associated with the extrusion 
of the volcanics of the " First " and " Third " periods only. 

Numerous faults of greater or less magnitude have affected the rock-masses of the 
subdivision, but as they rarely give topographic expression to the land-surface their 
presence is only revealed by mining operations. 

A general earth-movement involving the tilting of the whole Hauraki land-mass on a 
north-east and south-west a.xial line, with attendant elevation in the north and west 
and subsidence in the south and east, appears to have been in progress from middle 
Tertiary to late Pliocene times. This is deduced from the general disposition of the 
rock-masses, also from the existence of many sunken river-mouths on the south-eastern 
coast-line of the peninsula. The most recent movement, however — a minor one — was 
an elevation as registered l)v the Kauaeranga terraces at the south-westeni side and the 
Orokawa raised beaches on the south-eastern side of the peninsula. 

At or shortly following the close of the Pliocene period volcanic activity ceased in 
this region, and the main constructive geological process has been the in-filUng of bays 
and inlets l)y tiuviatile agencies. 

Table ok Formations. 

The geological formations occurring in the subdivision are, tabulated in order of 
age, as fol'ows : — 

Upper Eocene or Miocene (?). 

Tertiary volcanic rocks of the " Firat Period." 

Andesitic, dacitic, and rhyoUtic tuffs, breccias, and lava-flows. 
Miocene. 

Tertiary volcanic rocks of the "Second Period" (Beeson's Island Series). 

{a.) Older : Andesitic and dacitic tuffs, breccias, agglomerates, and lava- 
flows. 
(h.) Younger : Andesitic and dacitic tuffs, breccias, agglomerates, and lava- 
flows. 
Pliocene. 

Tertiary volcanic rocks of the " Third Period." 

Rhyohtic and dacitic tuffs, breccias, agglomerates, and lava-flows. 
Post-PUocene and older. 

Intrusive igneous rocks of various period:". 
Andesites, dacites, and rhyoUtes. 



38 

Pleistocene and Recent deposits. , 

River-flats, river-terraces, swamp deposits, harbour muds, sea-beaches, drifting 
sands, and talus debris. 
Geological formations, one or both of which may be inferred to exist at the deeper 
horizons in the subdivision, since they occur both to the northward and westward of its 
confines, are, — 
Pre-Jurassic. 

Tokatea Hill Series. 

Argilhtes and grauwackes, with interstratified beds of igneous material. 
Jurassic. 

Manaia Hill Series. 

Argillites, grauwackes, grits, and fine conglomerates. 

Pre-Jurassic and Jurassic Stratified Rocks. 

The basement rocks of the Hauraki Peninsula consist of folded strata of pre- 
Jurassic and Jurassic age. In the Coromandel Subdivision, which comprises the northern 
part of the peninsula, they have very considerable development. In the Thames Subdi\T- 
sion, farther southward, these rocks cover at the existing surface a very much more Umited 
area ; and in the Waihi-Tairua Subdivision they are deeply buried beneath the volcanic 
rocks, and have not been encountered in the deepest mine-workings. 

The pre-Jurassic and Jurassic rocks are respectively the Tokatea Hill Series and the 
Manaia Hill Series of the Coromandel and Thames subdi\'isions, described in Bulletins 
Nos. 4 and 10 (New Series). 

" The rocks of the Tokatea Hill Series consist of thin-bedded, dark-coloured argilhtes, 
grauwackes, and interstratified beds of hghter-coloured igneous material — altered rhyolites 
and rhyolitic tuff or ash, locally termed ' felsite.' In addition, rocks exist which show 
hthological gradations between the ordinary sedimentaries — argillites and grauwackes— 
and the interbedded rhyohtic tuffs. These strata are intruded to a much greater 
extent than the overlying Jurassic sediments by dykes of andesite and poi"phyrite. 
Though highly folded the Tokatea Hill Series shows no signs of dynamic metamorphism, 
and even in the actual vicinity of the dykes the strata are but shghtly affected by 
contact metamorpliism. The interbedded rhyohtic tuffs, however, are altered and 
pyritized by the hydrothermal agencies which have effected the propyUtization of con- 
siderable masses of the overlj'ing andesites. The strata of this series have so far 
afforded no fossils, and their age is therefore unknowm. In the classification of pre\'ious 
geologists* they have been referred either to the Devonian, the Carboniferous, or the 
Triassic period. 

" The rocks of the Manaia Hill Series consist of fine conglomerates, grits, grau- 
wackes, and argiUites, and present a marked uniformity in mineralogical composition 
wherever encountered in the Thames Subdivision or elsewhere in Hauraki." 

The fossils Inoceramus haasti and Belemnites sp., indicating an Upper Jurassic age, 
have been found in the fine conglomerate beds of certain locahties. 

Regarding the general structure of both the pre-Jurassic and Jurassic strata it may 
be said that the strike of the rocks, or the main axis of the folding, is nearly conform- 
able with the trend of the Hauraki Peninsula, and, taking a broader view, mth the older 
of the two main fines of folding which are evident in the North Island of New Zealand. 

The argilhtes and interbedded felsites of the Tokatea Hill Series have afforded 
auriferous veins at Tokatea Hill, Tiki, and Manaia (Coromandel), and at Tapu (Thames). 
Similar veins occur in the argilhtes and fine conglomerates of the Manaia Hill Series at 
Kuaotunu (Coromandel). 

* See Appendix, Bulletin No. 10. 



39 

Igneous Rocks. 

(1.) tertiary volcanic rocks of the " first period." 

General Statement. 

The Tertiary volcanic rocks of the " First Period " cover an area of about 23- 17 
square miles in the Waihi-Tairua Subdi\asiou, and are essentially of prime importance 
in that they constitute the main " auriferous series." They arc, with the exception 
of a local development of acidic rocks which forms the mining country of Owharoa, 
entirelv semi-basic or intermediate in character. 

The semi-basic rocks consist of andesitic and dacitic tuffs, breccias, agglomerates, 
and lavas, and are fomid comparatively fresh and in all stages of alteration and 
decomposition. The petrological examination of numerous rock-sections indicates that 
there exist only a few general hthological types, and that these types are closely related 
to one another. Practically none of the lavas shows vesicular structure. 

The acidic member of the series is not a particularly definite sjiecies, and may 
perhaps best be designated a dacite-rhyolite. Its existence recalls somewhat similar 
rocks associated with the " First Period " volcanics in the Coromandel Subdivision.* 

Anv dehnite order of succession is seldom recognizable among the different members of 
this great volcanic formation, and, owing to the absence of well-marked types and to the 
persistence of propylitic alteration and surface-decomposition, it is difficult to estabUsh the 
identity of a particular flow rock or of a breccia-bed, even in two neighbouring areas. 

These volcanic rocks are piled up in almost mountainous masses, rising in places to 
elevations of 2,000 ft., and, again, have been proven in the southern portion of the area to 
persist to and beyond a depth of 800 ft. below sea-level. The usual land-forms characteristic 
of crateral vents have been obUterated, owing to extensive modification by agencies of 
subaerial erosion. 

Age. 

The age of this series has, in Hulletins Nos. 4 ajid lU, dealing respectively with the 
Cbromandel and Thames subdivisions, been assumed to range from Upper Eocene to 
Lower Mioceiu\ and no further evidence bearing on this question has been afforded by the 
examination of the area under review. 

Distribution. 

Tlie " First Period " volcanics are exposed in three separate locaUties — (a) in the 
Puriri Valley and vicinity ; (6) throughout a belt extending southward from Maratoto, 
in the Hikutaia watershed, to Owharoa, on the north bank of the Ohincnuiri River ; and 
(c) at Martha Hill and the Union-Silverton hills, Waihi. 

The most northerly exposure is that occurring within the valley of the Piuiri .Stream, 
draining to the western seaboard. This is continuous westward with an area mapped in 
the Thames Subdivision. To the southward the " First Period " rocks extend into the 
Oiuahu Valley, and to the eastward are traceable, although underlying the " Third Period " 
rhyohtes, to the Golden Belt Mine at Neavesville. 

A much more extensive belt is that extending from Maratoto to Owharoa, a distance 
of nine miles, with an average width of two miles and a quarter. This stretch of country, 
as the maps will show, is drained by tributaries of the Hikutaia and Komata streams, and 
by the Waitekauri and certain small creeks at Owharoa, tributaries of the Ohinemuri River. 
It encloses the whole of the mining country of Maratoto, Peel's Creek, Komata, Golden 
Cross, Waitekauri, and Owharoa. 

The Waihi area, although the smallest, has proved economically by far the most 
important. The outcrops of the older rocks here form Martha Hill and the Union-Silverton 
group of hills — small " islands " or inUers, together measuring not more than 320 acres 

• BuUetin No. 4 (New Series), N.Z. G.S., p. 64. 



40 

^-surrounded by younger volcanics. As the special plans and sections of the Waihi 
area will show, the older volcanics — the dacites — have a more extensive development at 
the deeper horizons. 

Petrohgij. 

In appearance the unaltered andesites and dacites of this series are usually close- 
grained, finely porphyritic, black or greyish-black rocks, exhibiting small scattered 
ghstening phenocrysts of plagioclase feldspar and ferro-magnesian minerals. Weatliering 
or partial alteration almost invariably accentuates the porphyritic character of the rocks, 
causing the phenocrysts to stand out more prominently in the matrix, and thus gi^^ng 
rise to coarser textures than are possessed by their fresher representatives. These weathered 
or partially altered rocks generally assume greenish tints, owing to the development of 
chlorite. 

The associated tufEs, breccias, and agglomerates are usually well consoUdated. but are 
everywhere considerably altered. The fragmentary material is identical in raineralogical 
character with the rocks occurring as lava-flows or intrusives. A breccia containing 
angular inclusions varying from 2 in. to 5 in. in diameter, set in a fine-grained matrix, 
is probably the most common type. Some of these fragmental rocks are evidently 
autoclasts or brecciated flows. 

No fragment of the basement sedimentaries through which the volcanics have been 
extruded has been found in the fragmental rocks of this series, or. it may be added, 
in any of the younger series. 

PropyUtic alteration is widespread in connection with the " First Period " volcanics, 
and various transition-stages between the fresher rocks and the propyUtes are recogniz- 
able. Advanced propyhtization has resulted in both the lavas and the fragmentals being 
transformed to a somewhat similar product — a greenish, purphsh-grey, light-gi'ey or white, 
moderately hard rock — in which white chalky-looking altered feldspars and secoudar}' pyrite 
can alone be readily identified. 

The andesites and dacites, more especially in their altered condition, are very prone 
to surface-weathering, and are frequently covered to a considerable depth with the waste 
resulting from their disintegration. This weathered material is, owing to the formation of 
hydrous ferric oxides, coloured various shades of red, brown, and yellow. 

The tendency of many of the andesitic and dacitic lavas, and also the inclusions in 
the breccias, to alter or weather spheroidally is an interesting phenomenon, and cores of 
hard fresh rock enclosed in exfoliating softer shells are of common occurrence. 

The petrography of the various rocks of the series is described in detail in two 
volumes entitled " Rocks of Cape Colville Peninsula,"* and it has also been discussed 
in bulletins deahng with the Coromandel and Thames subdivisions. Rocks from Waihi 
itself have also been described by Morgan, Finlayson, and others. From the same series 
mthin the Waihi-Tairua Subdivision numerous sections have been cut and examined 
microscopical^, mainly with the object of assisting in the mapping of the boundaries 
between the older volcanics — the " auriferous series " — and the Beeson's Island volcanics 
(a non-productive or poorly productive series). It may be stated that no types other 
than those described in the reports named have been here identified. 

Pyroxene -andesites, hyperstheue-andesites, augite-audesites, and honiblende-andesites 
are represented. Rarely, however, does a single ferro-magnesian mineral exclusively 
occur in these rocks ; and, as the relative proportion of the subsidiary mineral increases, 



* 1905-6, Sollas and McKay. 

Note. — The grouping of the various rocks according to age by McKay, and consequently the mappiuj,'. 
differ materially from the grouping and mapping in this bulletin. Tlie locality assigned to each rock in the 
volumos named, however, can be approximately ascertained from a perusal of the maps accompanying the 
present report. 



41 

transitional types, such as hornbleiide-hypersthene audesite and hypersthene-lionibleiidc 
aiidesite, may be distinguished. In the pyroxene-andesites, which are apparently the 
most common, augite and hypersthene occur in approximately equal proportions. 

The dacites are mainly rocks of andesitic type, in which quartz occurs as phenocrysts. 
They contain the same ferro-magnesian and other constituents as the normal andesites, 
and, indeed, arc separable from the latter by no hard-and-fast line. 

Under the microscope the predominant feldspars of both the andesites and dacites 
are disposed as isolated crystals or aggregates of crystals. They range from andesinc 
to labradorite, and exhibit the multiple twinning, zoning, banding, and all the charac- 
teristics common to these minerals. The spareely scattered quartz grains of the 
dacit«s have rounded outlines, not infrequently broken by deep bays resulting from 
corrosion by a Huid magina. 

The ferro-magnesian minerals are generally more or less altered to chloritic serpentinous 
material, carbonates, iron-oxide, &c. Hypersthene is apparently the most common : but 
in many rocks augite is present iii approximately equal proportion, and occasionallv 
becomes predominant. Hornblende rarely occurs in a fresh state, but the lozenge- 
shaped pseudomorphs in comminut^'d magnetite, &c., seen in many rocks are indicative 
of the former presence of tliis mineral. Of the other original minerals, ilmenite and 
magnetite — with the alteration-products, leucoxene and siderite^ — are the most abundant. 
Apatite can generally be observed as small needles in the feldspai"s. Zircon occurs as 
occasional small crystals in phenocrysts of earlier generation. Biotite is rarely seen 
in the older andesites. although it is present in some of the younger semi-basic dyke 
rocks. 

The groundmass of these volcanics varies considerably in amount in different 
sections, but. as a rule, forms half or more than half of the rock. The mi( lopo-cilitic 
type of groundmass is the most common. In this a mosaic of crystalline grains of 
irregular jagged outHne (quartz, according to SoUas) enclost-s the feldspar microliths, &c. 
When the felds])ar laths are closely packed together, generally in flow alignment, the 
groundmass is perhaps better designat^'d " pilotaxitic." The glassy or hyalopihtic 
type also occurs, but is by no means common in the ' First Period " andesites and 
dacit^'s. The nature of the groundma.ss in many rocks is, as may be expected, 
obscured by calcite and other secondary products. 

The rhyoUtes or dacite-rhyolites, which are conlined to the vicinity of Owharoa, 
are greenish-grey or greenish-white lustreless rocks, showing phenocrysts of (|uartz 
and feldspar, and occasionally altered ferro-magnesian minerals. They generally exliibit 
spheruUtic structure. Their more altered and weathered equivalents are fairly coarse- 
textured, granular, and incoherent. 

Under the microscope these rhyolitic rocks exhibit a matrix consisting of spheruhtic 
material, with occasionally mosaic quartz filhng interstices. The phenocrysts are ortho- 
clase. probably containing soda, plagioclase (ohgoclase-andesine). <)uartz (corroded grains), 
hornblende (pseudomorphosed), pyroxene, and biotite. Magnetite, zircons, and apatite are 
sparingly present. The rock appears to vary considerably from point to point, specimens 
from some locahties showing no orthoclastic con.stituent ; others, again, no pvroxenes. In 
the field, too, a gradation from the more acidic type to the semi-basic type appears 
traceable. The conditions are suggestive of a minor extrusion of an acidic magma which 
had stoped its way through andesitic rocks, thereby undergoing partial changes of 
composition. 

The classification of the rocks enclosing the quartz veins at ^^'ai}u itself has recently 
given rise to considerable discussion. These, in general appearance, are normal quartz- 
bearing andesites or dacites, and under the microscope show all the characteristics of such 



(1-) 

Per Cent. 


(2.) 
Per Cent. 


(3.) 
Per Cent. 


(4.) 
Per Cent. 


(5.) 
Per Cent. 


58-45 


59-95 


56-80 


57-20 


58-02 


16-50 


17-34 


16-19 


16-39 


17-04 


0-24 


0-79 


0-95 


301 


Nil. 


4-42 


4-35 


4-42 


313 


5-04 


0-43 


0-47 


0-55 


0-22 


0-42 


3-76 


4-05 


3-70 


4-44 


4-24 


5-45 


2-65 


7-56 


3-31 


4-29 


0-9G 


2-21 


113 


1-58 


1-36 


2-16 


2-63 


3-81 


3-60 


3-48 


0-78 


0-79 


0-82 


0-60 


0-93 


2-83 


2-20 


0-1)5 


3-60 


1-14 


4-32 


2-88 


4-18 


316 


3-82 



42 

rocks, excepting that a considerable proportion of the feldspars is orthoclastic. Chemical 
analyses, as the following tabulation will show, are also indicative of the relatively 
high potash-content in these rocks : — 

Silica (SiOa) .. 
Alumina (AUOg) 
Ferric oxide (FcjOg) 
Ferrous oxide (FeO) 
Manganous oxide (MnO). . 
Lime (CaO) . . 
Magnesia (MgO) 
Soda (Na^O) . . 
Potash (KgO) . . 
Titanium-oxide (TiOj) . . 
Carbonic anhydride (COg) 
Loss on ignition (ex- 
cluding CO2) 

100-30 100-31 100-16 100-24 99-78 

(1.) No. 5 level, Waihi Mine, chamber of No. 1 shaft. Altered hornblende- 
pyroxene dacite. 

(2.) No. 8 level, Waihi Mine, Wheel Pass crosscut, 70 ft. from foot-wall of Martha 
lode. Highly altered and pyritized dacite. 

(3./ No. 9 level, Waihi Mine, hanging - wall country of Martha lode. Highly 
altered dacite. 

(4.) No. 4 level, Waihi Grand Junction Mine, south-east crosscut, 25 ft. from 
foot-wall of Empire lode. Altered hornblende-pyroxene dacite. 

(5.) No. 4 level, Waihi Grand Junction Mine, south-east crosscut, 12 ft. from 
. foot-wall of Royal lode. Altered hornblende-pyroxene dacite. 

All the vein-bearing rocks at Waihi are considerably altered. Even specimens (4) 
and (5), which megascopically appeared almost fresh — the best obtainable — showed 
considerable alteration when viewed under the microscope. The question as to how 
much of the orthoclastic constituent is primary and how much secondary is thus 
rendered difficult. That valencianite (secondary orthoclase) occurs in some of the 
altered rocks is undoubted.* Almost every section cut, however, showed untwinned 
feldspars of low refractive index, which closely simulate original orthoclases, and as 
such have been regarded by SoUas, who has consequently classed the rocks as pyroxene- 
rhyohtes. In many sections examined by the writers and by others the occurrence of 
unmistakable transitions from lime-soda feldspar — acid labradorite or andcsine — to alkali 
feldspar has been recognized. Furthermore, the proportion of orthoclastic feldspars to lime- 
soda feldspars seems to increase with the increase of propyUtic alteration, although it must 
be admitted that the chemical analyses submitted hardly seem to support this statement. 

In view of the relatively low sihca-percentage in the rock, and the fact that very many 
of the orthoclastic feldspars are in reahty pseudomorphs after oHgoclase, the writers agree 
with Morgan, Maclaren, and Finlayson in classing the Waihi vein-bearing rocks as dacites. 
It seems probable, however, that these dacites, in common with certain other andesitic 
rocks in the district,! originally contained a higher percentage of potash than is usual in 
rocks of this type. 

* See p. 54. -f See analysis " Second Period " andesite from Ramarama Creek, p. 45. 



43 



(2.) TERTIARY VOLCANIC ROCKS OF THE " SECOND PERIOD " (bEESON's ISLAND SERIES). 

General Statement. 

The " Second Period " volcanics, or Bcesoii's Island Series, consist entirely of 
andesitic and dacitlc tuffs, breccias, agglomerates, and lavas. With these effusive rocks 
are associated dykes of andesite or dacite, which in places, however, cannot be distinguished 
from the lava-flows. 

The volcanics of this period in the particular area under review appear divisible 
into (o) an older group, (h) a youiig(!r group. In many localities, however, volcanic 
activity seems to have been practically continuous, or punctuated only by relatively short 
intervals of quiescence. The contact-hue, therefore, between these two groups is often 
purely an arbitrary one. 

The " Second Period " volcanics. as the maps will show, cover a relatively great 
extent of country in the Waihi-Tairua Subdivision. Their great development is, from 
a mining point of view, particularly unfortunate, as no epoch of metallization affording 
important ore-deposits appears to have been connected with their extrusion. In certain 
locahties the " Second Period " andesites and dacitcs enclose quartz veins, from which small 
shoots of ore have been mined, but there is cons derable evidence in support of the view 
that metalhzation in these cases is referable to the intrusion of the rlivolitcs — the "Third 
Period " volcanics. 

In general, the lavas of the Beeson's Island Series, and particularly those of the 
younger group of this series, are less crystalhne in character than those of the "' First 
Period." The fragmental rocks, furthermore, contain a greater proportion of heavy 
agglomcratic material, and are not so well consohdated. Advanced propylitic alteration 
has affected only comparatively local areas in the country covered by these volcanics, 
a feature which stands in marked contrast to the widespread alteration of the rocks of 
the " First Period." 

The contact-line or old land-surface between the volcanics of this and the older 
series is in places marked by the occurrence of beds carrying carbonaceous material. 
Again, thin coaly partings occur at many places within the "Second Period" complex 
itself, marking minor pauses between successive manifestations of volcanic activity. It 
should be here stated that in many cases, on account of the general similarity in 
original composition of the earlier and later andesites, the question of determining more 
than an approximate boundary between the rocks of the two series often baflles solution, 
even when field-work is supplemented by microscopic study. It will be noticed, on 
comparing the maps accompanying this bulletin with those appearing in earher reports, 
that the writers have referred considerably more of the Tertiary volcanic complex to 
the Beeson's Island Series than have previous investigators. 

A(je and Correlation. 

A Miocene age has in the Coromandel and Thames bulletins been tentatively 
assigned to these " Second Period " rocks, and no further evidence bearing on the 
question has been afforded by the survey of the area under review. 

The separation of the volcanics of the " Second Period " from those of the " First 
Period " involves considerations of the general structure of the rock-complex, the rela- 
tionsliip of certain of the quartz-vein systems to the enclosing and the neighbouring rocks, 
as well as the mineralogical and physical character of the various rocks constituting 
the two series. The subdivision, however, of the " Second Period " volcanics themselves 
into an older and a younger group depends on geographical distribution, on disposition, 
and on the degree of consohdation of the fragmentals, rather than on marked petrological 
differences in the individual rock-species. 



44 

The uucouforniity between the " First Period " or vein-bearing rocks, and the 
" Second Period " or (at this locahty) non-vein-bearing rocks, is nowhere better shown 
than in the mine-workings at Waihi (see special sectional plans). At Waitekauri similar 
conditions exist, the " Second Period " andesites and dacites forming the whole of the 
country to the east of the main stream. Prospecting- workings in these rocks failed to 
reveal any extension of the Golden Cross vein-system worked immediatelv to the west- 
ward. Furthermore, scarcely a vestige of quartz or a " colour " of gold is present in 
the debris of any of the creeks draining this eastern side of Waitekauri Vallev. No 
unconformity or general change in character is recognizable in the extensive belt of 
andesites and dacites extending from Waihi and eastern Waitekauri in the south to the 
Tairua Valley in the north. The rocks of the whole of this belt have therefore been 
mapped as volcanics of the " Second Period," or Beeson's Island Series, and more 
particularly as the older group of this series. 

Other minor belts or exposures have been mapped mainly on the hthological simi- 
larity of their rocks to those of this main belt indicated. 

The younger group of the " Second Period " volcanics is mainly contined to the 
western side of the water-parting of this portion of the peninsula. Tiie lavas and 
fragmentals. on the whole, exhibit a more definite bedded structure than do those of the 
older group, and, furthermore, the fragmentals are more loosely consolidated, and contain 
much more heavy agglomeratic material than those of earlier extrusion. The position 
in sequence of this particular group of rocks has been recognized by all previous 
investigators, although opinions may have differed as to the actual mapping of particular 

belts. 

(a.) Older Group of the Beeson's Island Series. 

Distribution. — As the maps will show, by far the most extensive stretch of comitrv 
covered by this group of rocks has unbroken continuity northward from the Waihi 
Plain to Whangamata. forming almost one-half of the Ohinemuri Survey District, and 
in many places extending eastward to the coast-hne. Further westward a belt of these 
volcanics is interposed between the "First Period" rocks of the Maratoto-Owharoa belt 
and the younger group of the Beeson's Island Series, and is separated from the latter 
in several places by seams of impure coal and carbonaceous shales. 

Northward of the locaUties mentioned, irregularly shaped areas of these rocks occur 
in Hikutaia Valley and throughout almost the whole of the comitry drained by the 
headwaters and western tributaries of Tairua River. Smaller isolated patches (inhers) 
throughout the WTiarekawa and WTiangamata watersheds either stand above the " Third 
Period " rhyohtes, owing to their greater elevation, or have been exposed by agencies 
of denundatiou. 

In the Whitianga Survey District a coastal belt of these rocks extends noilhward 
from the entrance of Tairua Harbour to Hot Water Beach, a distance of over ten 
miles, and is throughout bounded to the westward by rhyohtes. 

Structure and Petrology. — In general, many of the flow rocks differ little from those 
described in connection with the " First Period " series. Andesites and dacites. with a 
glassy (hyalopihtic) or obscurely micropa'cihtic groimdmass, however, have a dense 
black and occasionally almost a vitreous appearance, which is seldom observable among 
those of the older series. 

As the mapping will show, lavas greatly predominate over the breccias throughout 
the stretch of country extending from Tairua to Waihi. Hypersthene-andesites and 
pyroxene-andesites, or similar rocks containing hornblende, are the predominant types. 

The tuffs and breccias show rocks of the same petrological character as the lavas. 
The consoHdation of these fragments is usually not as advanced as in the " First 
Period "' volcanics, but is, as a rule, better than in that of the younger group (b). 



45 

A chloritic alteration is \\adcspi'ead throughout these rocks, l)ut advanced propy- 
litization is confined to rather local areas where quartz veins or siliceous sinter-deposits 
are developed. 

The detailed microscopic characters of the rocks have been fully described in the 
reports already cited, and the examination of numerous rock-sections cut during the course 
of the present survey has revealed no new types. It is sufficient here to remark that 
hypersthene-andesites. pyroxene-andesites. augite-andesites, hornblende-andesites, and 
dacites are represented throughout the area. In regard to the groundmasses of the 
various rocks, it may be stated that out of ninety sections examined^ — and these were 
fairly representative of the whole group — about two-thirds showed a micropa'cilitic or 
obscurely micropnecilitic structure, and one-third the hyalopihtic or glassy structure. 

The following chemical analyses were made : — 

F 
Sihca (SiOo) . . 
Alumina (AUOa) 
Ferric oxide (FcoO.,) 
Ferrous oxide (FeO) 
Manganous oxide (MnO) 
Lime (CaO) . . 
Magnesia (MgO) 
Soda (Na,0) .. 
Potash (KoO) 
Titanium-oxide (TiO.). . 
Carbonic anhydride (COj) 
Loss on ignition (excluding CO^, ) 

<)<»-7l lOO-a") 

(1.) Waihi Grand Junction Mine, No. 3 level. iTornblende-hypersthene andesite, 

containing a little quartz. 
(2.) Ramarama Creek, north of Whiritoa. Microprecilitic pyroxene-andesite. 
The relatively high potash-content in these andesitic rocks — particularly in (2), 
which was fairly fresh, was collected from a non-propylitized area, and apparently showed 
under the microscope only plagiodase feldspars — is rather remarkable. This, taken 
in conjunction with the high percentage of potash in the older vein-bearing dacites 
at Waihi, suggests that throughout portions, at least, of southern Haiuaki tlic magma, 
from which the semi-i)asic lavas were extruded at relatively widel\- separated time- 
intervals, was abnormally liigh in the potash-alkali. At Thames the greatest ratio of 
potash to soda in any fairly fresh andesite analyzed was as 1-80 : 2-06. 

(b. ) Yoiin'fr (Irotip of the Retnon'i Island Series. 

Distribution. — The younger group of the Becsoii's Island Series is brokenly continuous 
along the western boundary of the subdivision, almost from one end to the other. 
Many of the areas mapped are the easterly continuations of areas mapped in the 
Thames Subdivision. Others, again, have extension eastward from the alluvial flats of 
the Thames-Hauraki Plain. To the eastward these belts are overlain by younger 
rhyohtes, or themselves flank older rocks. 

Structure and Petrology. — The lavas of this group show similar mineralogical compo- 
sition and similar types to the earlier members of the series, but microscopic examination 
of many representative specimens shows that over 60 per cent, of these andesites and 



jr Cent. 


(2.) 
Per (.'eiU. 


55fil 


61-77 


18-46 


16-48 


0% 


2-38 


r)-62 


3-08 


(ilf) 


0-15 


7 -20 


5-80 


:5-21 


3-03 


117 


1-46 


2-78 


3-72 


U-74 


0-75 


218 


Nil. 


1-63 


1-73 



46 

dacites have a glassy or hyalopilitic groundmass. In the field these glassy rocks when 
partially weathered assume a peculiar trachytic appearance, a fact which led certain 
earUer investigators to regard them as trach}'tes. 

The tuffs, breccias, and agglomerates are relatively abundant, and generally show, 
together with the intercalated lava-streams, a rude stratification. Bare rock-benches, 
showing obvious bedding disposed at low angles, are conspicuous features on the hill- 
sides between Omahu and Paeroa. As already remarked, these fragmental rocks are 
very poorly consohdated. Angular blocks of lava ranging up to 2 ft., 3 ft., or even 
5 ft. in diameter are by no means uncommon in the agglomerate bods. Fine-grained 
tufaceous material constitutes the cementing medium or matrix, but occasionally small 
angular lapilli alone fill the spaces between the hea^^er inclusions. 

The rocks of this group developed in the Waihi-Tairua Subdivision differ httle from 
beds in the typical locality, Beeson's Island, which lies at the entrance to Coromandel 
Harbour, and is described in Bulletin No. 4. 



(3.) TEETIARY VOLCANIC ROCKS OF THE " THIRD PERIOD." 

General Statement. 

The volcanic rocks of the " Third Period," in contradistinction to those of earher 
periods, are entirely acidic or semi-acidic in character. They consist of pyroclastics — 
puiniceous tuffs, breccias, and agglomerates — through which have been extruded flows of 
rhyolite, and, to a less extent, of dacite. 

These rhyoUtic rocks cover more than half the subdixasion, and there is e\idence that 
they formerly transgressed considerable areas wliich now, owing to denudation, show only 
andesitic rocks. Over relatively great stretches of country, particularly in the northern 
portion of the subdivision, these " Third Period " volcanics persist to unknown depths. 
Elsewhere they are observed to overUe or break through an irregular surface of the older 
volcanics. The contact-fine or unconformity is often marked by the occurrence of earthy 
beds containing carbonaceous material. 

The rhyolitic tuffs and lavas have in places been subjected to hydrothermal altera- 
tion, which' was attended by metalUzation of certain zones and pipes or with the forma- 
tion of more definite ore-bearing fissure-veins. So far, the veins occurring wathin the 
belts of intrusive or flow rhyoUtes have proved the more profitable. 

Age. 
The age of these rocks is usually, and probably rightly, regarded as Phocene. Weil- 
preserved fern and leaf impressions and carbonized tree-tnuiks occur in the carbonaceous 
basal tuffs in the \icinity of Table Mountain, in Rangihau Valley, and elsewhere, but 
the specimens collected have not yet been identified. Casts of the fresh-water mussel 
(Unio aucklandicus) are also abundant in certain mudstone-layers in the same locahties. 

Distr'ibution. 
As the " Third Period " volcanics have been extruded from many vents upon a land- 
surface of very uneven configuration, and have been subjected to considerable erosion, 
they exhibit, in the main, markedly irregular distribution. As the maps Avill show, they 
cover about two-thirds of the whole Whitianga Survey District, over half of the Tairua 
Survey District, and relatively extensive stretches in the Ohinemuri and Waihi North 
survey districts. 




Plate X. — Rhtolitk, showing markkd Columxah STRVCTruK. From Uppkr rioROE of Kaiaeraxga 

River. 



Facnp. 47.] 



47 

Structure and Petrology. 

Fragmental rocks — tuffs, breccias, and agglomerates — are by far the most abundant 
members of this series ; and through these beds the lavas were extruded at various 
points, and in places overflowed, forming thick sheets. Some of the lava plugs which 
filled the conduits have been laid bare by agencies of denudation, and now form pro- 
minent features of the landscape. Several of these old plugs and dissected flows occur 
in the high country between the Kauaeranga and Tairua rivers, and, again, between the 
Tairua and Wliitianga watersheds. 

The fragraentals, which in general arc of a creamy -white colour, with, in the coarser 
varieties, darker inclusions, vary in character from tufaceous mudstoncs to fairly heavy 
agglomerates. The predominant type is one in which tlie larger isolated fragments of 
flow rhyolite and andcsitic material rarely exceed J in. in diameter. Pumice is almost 
invariably present in tliis and all tlie other fragmentals ; splinters of pitclistone are also 
common. These fine-grained agglomerates frequently show no signs of bedding, and are 
intersected by relatively few joint-planes. 

The occurrence of a considerable amount of andesitic material in rhyolitic fragmentals 
erupted through an older land-surface of semi-basic rocks is to be expected, but the 
evenness, both in the distribution and grade, of these andesitic inclusions is often 
remarkable. 

The tufaceous mudstones and grit-beds, which are particularly common in the Rangi- 
hau and Kapowai valleys, are disposed as thin-bedded alternating strata, dipping usually 
at low angles. The incUnation of these beds may be in part determined by original 
conditions of accumulation, but is evidently mainly due to the intrusion of more recent 
rocks, to faulting, or to regional earth-movements. The predominance throughout the 
subdivision of incUnations at low angles to the south-eastward is indicative of regional 
tilting of the whole land-mass in this direction subsequent to the Pliocene eruptive 
activity. 

The mudstones frequently form the basal members of the series, but in the upper 
Kauaeranga and many other locahties heavy agglomerate beds, consisting mainly of 
angular fragments of andesite, represent the earliest products hurled from explosive 
craters. 

The weathering of these rhyoUtic fragmentals frequently gives rise to bizarre land- 
forms. Vertical scarp-faces and outlying stacks are not uncommon. These white walls 
of rock, frequently scored with vertical flutings or corrugations, recall familiar topography 
in limestone country. 

The petrography of the flow rocks, both rhyolitcs and dacites, has been described in 
detail in the two volumes " Rocks of the Cape Colville Peninsula," over ninety specimens 
from the Waihi-Tairua Subdivision and neighbourhood having been examined. Many 
sections have been cut and examined by the writers, but no new types have been 
revealed. 

The predominant massive rhyoUte is a pinkish-grey banded rock, which either 
megascopically or under the microscope shows a marked spherulitic structure. The 
usual phenocrystic minerals are sanidine, plagioclase, biotite, and quartz. Minor accessory 
minerals, one or more of which may be present, are magnetite, leucoxene, tridymite, and 
zircon. The occurrence of hornblende and pyroxene is not uncommon. Transformation 
of the rhyohtes into quartz-sericite rocks, particularly in the vein-bearing areas, is a 
conspicuous feature. 



48 



The following ii- an nnalysif^ of the well -ban dcrl flow rhvolite exposed in the road- 
ciittings at Puketui, Tairua : — 

Per Cent. 
Silica (SiOa; . . . . . . . , . . . . 73-76 



Alumina (AljO^) 

Ferric oxide (FcjOa). . 

Ferrous oxide (FeO) 

Manganous oxide (MnO) 

Lime (CaO) 

Magnesia (MgO) 

Soda (Na^O) 

Potash (K.O) 

Titanium-oxide (Ti02) 

Carbonic anhydride (CO,) 

Loss on ignition (excluding COo) 



12-96 
2-20 
0-36 

Nil. 
1-42 
0-75 
2-06 
4-50 
0-14 
Nil. 
2-0() 



100-15 

Certain relatively local developments of rhyolite almost resemble greyish homstones ; 
again, rhyoUtic glasses and pitchstones, generally exhibiting perhtic structure, occur here 
and there throughout the subdivision. 

Two special types of flow rhyoUtes form the plains of the Waihi Basin. The older 
is the pecuHar rock locally termed " wilsonite," which is fairly regularly jointed, and is 
extensively quarried for road-metal. The younger is a compact hght-grey rock of rather 
harsh texture, which is found in several places breaking through or overl\ang the former. 

The freshest specimens of " wnlsonite " obtainable show pinkish-grey surfaces, with 
dark lenticular flakes and streaks in parallel aUgnment, and on the whole present a 
\atreous sheen or lustre. Small phenocrysts of quartz and feldspar occur here and there. 
Inclusions of rounded fragments of andesite ranging up to about | in. in diameter are 
common. When weathered, the " wilsonite " simulates a grejdsh-white pumiceous tuff 
containing isolated fragments of andesitic material. 

Under the microscope the matrix of the rock, together with the dark lenticular 
streaks, is seen to consist almost entirely of glass, colourless to brownish, practically 
isotropic, and exhibiting marked fluxion structure. The feldspar phenocrysts are mainly 
andesine, and the quartz is generally in the form of corroded grains. Shreds of biotite, 
and occasionally pseudomorphs after pyroxene, occur. 

The rock is evidently a flow, in which a considerable amount of internal brecciation 
of the material of earher consolidation was continually taking place. The origin of the 
andesitic material is obscure. Rutley is disposed to regard it as iapilli rained on to the 
flowing lava by a neighbouring volcano. 

The greyish-white tridymite-bearing rhyohtes are compact rocks with a somewhat 
harsh texture, in wlvich minute glassy feldspars may be detected, and occasionally a flow 
structure. Very small dark andesitic fragments are usually noticeable, and Morgan* 
has recorded the occurrence of charcoal in certain specimens obtained from the Grand 
Junction shaft (110 ft. to 112 ft.), and in the chamber at No. 4 shaft, No. 3 level, 
Waihi Mine. Microscopic sections show a predominating glassy base with a fine corru- 
gated flow structure, in which are scattered small phenocrysts of ohgoclase or andesine, 
and in most cases tridymite. Small broken crystals of hornblende, augite and hyper- 
sthene, probably xenocrysts, are occasionally observable. 



* " The Igneous Rocks of the Waihi Goldfield," Morgan, P. G., Trans., vol. 4.3, 1910, 



53 

probably attributable to tectonic moveiueuts, which have from time to time been repeated 
in tlie Hauraki Peninsula along the north-east, or Ruahine-Alpinc, line of New Zealand 
folding. Lines of weakness (along which fissures would occur) estabhshed in the 
sedimentaries may have dominated the directions of fissuring in tlie superincumbent 
volcanic complex. It is not, however, to folding stresses and faulting alone that the 
actual fissuring may be referred. Many fissures have resulted from the contraction of 
the lava-flows and intrusive rocks on cooUng. Earthquake shocks propagated in the 
basement rocks have also more than likely played a prominent part in the fissuring of 
the volcanics. To the effect of a sharp shock on the rock-mass already in a state of 
tension has been attributed the extraordinary system of conjugate fissures represented by 
the Martha vein-system at Waihi. The principal Wailii reefs — the Martha, Empire, and 
Royal — trend almost east-north-cast, thus deviating considerably from the prevailing 
strike of the reefs of the i)eninsula. 

As is a common feature in many other mining fields, the fissuring of intmsive rock- 
masses in the area under review has frecjuentiy been found to have little extension beyond 
the Umits of the intrusives. This is the case both at Tairua Broken Hills and at Luck-at-Last 
(Whangamata), where the veins are confuied to intrusive rhyohtcs. At Waihi, too, a decided 
weakening of vein fissuring is noticeable beyond the limits of the main dacitic boss. 

It is a noticeable fact that more extensive fissuring has taken place near the surface 
than at the deeper horizons. In many mines veins approximately parallel and quite 
independent at the upper levels are found, when followed downward, to terminate on 
the hanging-walls of the more persistent reefs. 

Faulting along the vein fissures either before or after vein-filling has been a fairly 
general phenomenon. At Waihi most of the veins show evidences of this, but the 
amount of differential movement appears to have been slight. 

The Mineralizing Agents. 

The prime agencies of impregnation whi<h resulted in the deposition of vein-material 
as fissure-filling and as replacements of the wall-rocks were evidently hydro thermal 
solutions. The character of the veinstone and the nature of the alteration of the wall- 
rocks afford a clue as to the composition of these solutions in the various locaUtie^. 
Similar agencies, giving rise to rock-alteration, sinter-deposition, and almost certainly 
vein-formation, are to-day active at the hydrotheiraal centre of Rotorua, some fifty-five 
miles in a straight line from Waihi. Hot springs also occur along the western base of 
Mount Te Aroha, eleven miles from Waihi. 

While it is evident that by far the greater part of the minerahzation was effected by 
heated ascending solutions, the nature of portions of the veinstone indicate that vadose waters 
have effected considerable modification at later stages and at more superficial horizons. 

The eariiest mineralizing solutions which rose in the vein fissures at Waihi, Goldeji 
Cross, Komata, Maratoto, and Waihi Beach carried mainly carbonates, and deposited an 
enormous amount of calcite. The ores of these localities are of later origin than this 
calcite. The origin of the carbonate-content of these waters is obscure. It has been 
suggested that limestone -beds of the Torehine Series may underhe the volcanics in this 
particular area, and may have afforded the carbonate to ascending waters. This, however, 
is a vague hypothesis. The lime-soda feldspars of the semi-basic volcanics are, of course, 
a possible source of hme. No such widespread deposition of carbonates was, however, 
associated with the formation of veins in the neighbouring Thames and Coromandel 
subdivisions. It may be mentioned, too, that in these subdivisions the andesites and 
dacites, on the whole, carry almost twice as much lime as do those in the area under 
review. The chemical character of the rocks enclosing the veins would appear to have 
had but little effect. The rocks of Waihi, Golden Cross, Komata, and Maratoto are 



66 

The liiglily altered rliyolites in the tield closely resemble the propylitized andesites 
or dacitcs, but frequently the purphsh-grey colour of the less-altered rock and " the 
original llowuge-banding can be detected. Under the microscope the altered rhyohtes 
examined were found to consist mainly of quartz and of fine-grained sericite. Magnetite 
altering to Icucoxenc, pyrite. and a few small zircons are generally present. Some of 
the quartz Tuosaics are obviously replacements after phenocrysts, and, again, the grouping 
suggests replaced spheruhtes. Oxidation results in the formation of ferric hydrate as 
small rounded granules. The sihcification of the rocks in the vicinity of the veins is 
even a more pronounced feature than in altered andesitic and dacitic rocks. 



Mineralogy of the Vei:<-matepial. 

In the Waihi-Tairua Subdivision, as in other portions of the Hauraki Goldtield, the 
minerals which comprise the great bulk of the veinstones are few in number. If to 
these, however, be added the less common minerals which have from time to time been 
identified by various investigators, a fairly long hst results. 

The commonest gangue-minerals are quartz and calcite, the latter being often 
manganiferous. Hydrated sihca, kaohnite, and complex carbonates are not uncommon. 
Pyrite is the most abundant metalhc mineral, and with it are associated, in certain of the 
ores, sphalerite (zinc-blende), galena, and chalcojiyrite. In the oxidized veinstones 
limonitic products derived from the decomposition of pyrite are abundant, and black 
oxides of manganese are conspicuous where the parent vein-filhng contains manganiferous 
calcite. 

Non-metallic Minerals. 

Quartz. — Quartz, the commonest mineral of the veinstones, occurs in a great many 
forms, as the descriptions of the veins of the different mines will show. It varies from 
coarsely crystaUine to finely crystalhne and almost chalccdonic. The finely crystalhne 
varieties predominate. Platy quartz, pscudomorphous after calcite, is widespread through- 
out the mines of the southern portion of the subdivision. The rhombohedral form is 
here often perfect ; again, it can be ascertained only by microscopic observation. 
Mere rhombohedral shells of quartz with their interiors hned by drusy quartz are 
common. 

Amorphous and Cryptocrystalline Silica. — Jasper and chalcedony, forming veinlets 
and nests, are of widespread occurrence, especially in the rhyohtic lavas and breccias. 
The jasper is red, crimson, yellow, or more rarely ohve-green, in colour. The 
chalcedony is generally bluish-white or translucent, and is occasionally banded. Sihcified 
wood is frequently found within the rhyohtic tufl's. Some of this has undergone carbon- 
ation prior to sihcification. Gem opal of rather poor quahty is found sparsely distri- 
buted in a sihcified glassy rhyohte on Laycock's farm, Tairua. Small nests of it are 
also seen in dykes of rhyohte in' various locahties. Common opal occurring under similar 
conditions is more abundant. 

Calcite. — Calcite is, next t? quartz, th(f commonest vein-mineral, and almost com- 
pletely fills certain fissures. It occurs generally throughout the subdivision, and is 
especially conspicuous in the veins of Waihi, Golden Cross, Maratoto, and Komata. 
Much of the calcite is not pure, but contains some manganese-carbonate and a small 
percentage of magnesium-carbonate (see analyses, pages 106, I'-Vi). 

Efsomite. — Epsomite, the sulphate of magnesium, may be seen as small sparkhng 
stalactites in many disused drives. It is a product of the alteration of the wall-rocV 
rather than of the veinstone. 



53 

probably attributable to tectonic uiovemeuts, which have from tiiiie to time been repeated 
in the Hauraki Peninsula along the north-east, or Ruahine-Alpine, line of New Zealand 
folding. Lines of weakness (along which fissures would occur) established in the 
sedimentaries may have dominated the directions of fissuring in the superincumbent 
volcanic complex. It is not, however, to folding stresses and faulting alone that the 
actual fissuring may be referred. Many fissures have resulted from the contraction of 
the lava-flows and intrusive rocks on cooling. Eartlupiake shocks propagated in the 
basement rocks have also more than likely played a prominent part in the fissuring of 
the volcanics. To the effect of a sharp shock on the rock-mass already in a state of 
tension has been attributed the extraordinary system of conjugate fissures represented by 
the Martha vein-system at Waihi. The principal Waihi reefs — the Martha, Emj)ire, and 
Royal — trend ahnost east-north-east, thus deviating considerably from the prevaihng 
strike of the reefs of the peninsula. 

As is a common feature in many other mining fields, the fissuring of intrusive rock- 
masses in the area mider review has frecpicntly been found to have little extension beyond 
the Umits of the intrusives. This is the case liotli at Tairua Broken Hills and at Luck-at-Last 
(Whangamata), where the veins are confined to intrusive rhyoHtes. At Waihi, too, a decided 
weakening of vein fissuring is noticeable beyond the limits of the main dacitic "hass. 

It is a noticeable fact tfuit more extensive lissuring has taken place near the surface 
than at the deeper horizons. In many mines veins approximately paraflcl and i|iiitc 
independent at the up))er levels are found, when followed downward, to terminate oir 
the hanging-walls of the more persistent reefs. 

Faulting along the vein fissures either before or after vcin-iilUng has been a fairlv 
general phenomenon. At Waihi most of the veins show evidences of this, but the 
amount of difEerential movement appears to have been slight. 

'^< 
The Mineralizing Agents. 

The prime agencies of impregnation which resulted in the deposition of vein-material 
as tissure-filUng and as rej)lacements of the wall-rocks were evidently hydrothermal 
solutions. The character of the veinstone and the nature of the alteration of the wall- 
rocks afford a clue as to the com{)osition of these solutions in the various localities. 
Similar agencies, giving rise to rock-alteration, sinter-dej)osition, and almost certaiidy 
vein-fonnation, are to-day active at the hydrothermal centre of Rotorua, some fifty-five 
miles in a straight line from Waihi. Hot springs also occur along the western base of 
Mount To Aroha, eleven miles from Waihi. 

While it is evident that by far the greater pait of the mineruHzation was effected by 
heated ascending solutions, the nature of portions of the veinstone indicate that vadose waters 
have effected considerable modification at later stages and at more superficial horizons. 

The earliest mineraUzing solutions which rose in the vein fissures at Waihi, Oolden 
Cross, Konnita, Maratoto, and Wiiilii Beach carried mainly carbonates, and deposited an 
enormous amomit of calcite. The ores of these locahties are of later origin than this 
calcite. The origin of the carbonate-content of these waters is obscure. It has been 
suggested that Umestone-beds of the Toreliine Series may underhe the volcanics in this 
particular area, and may have afforded the carbonate to ascending waters. This, however, 
is a vague hypothesis. The Ume-soda feldspars of the semi-basic volcanics are, of course, 
a possible source of lime. No such widespread deposition of carbonates was, however, 
associated with the formation of veins in the neighbouring Thames and Corpmandel 
subdivisions. It may be mentioned, too, that in these subdivisions the andesites and 
dacites, on the whole, carry almost twice as much hme as do those in the area under 
review. The chemical character of the rocks enclosing the veins would appear to have 
had but httle effect. The rocks of Waihi, Golden Cross, Komata, and Maratoto are 



56 

The liighly altered rhyolites in the tield closely resemble the propyhtized andesites 
or dacites, hut frequently the purplish-grey colour of the less-altered rock and the 
ordinal flowage-banding can be detected. Under the microscope the altered rhyohtes 
examined were found to consist mainly of quartz and of fine-grained sericite. Magnetite 
altering to leucoxene, pj'rite, and a few small zircons are generally present. Some of 
the quartz mosaics are obviously replacements after phenocrj-sts, and, again, the grouping 
suggests replaced spherulites. Oxidation results in the formation of ferric hydrate as 
small rounded granules. The sihcification of the rocks in the vicinity of the veins is 
even a more pronounced feature than in altered andesitic and dacitic rocks. 



Mineralogy of the Yein-matepial. 

In the Waihi-Tairua Subdi\"ision. as in other portions of the Hauraki Goldfield, the 
minerals M-hich comprise the great bulk of the veinstones are few in number. If to 
these, however, be added the less common minerals -which have from time to time been 
identified by various investigators, a fairly long list results. 

The commonest gangue-minerals are quartz and calcite, the latter being often 
manganiferous. Hydrated sihca, kaohnite, and complex carbonates are not uncommon. 
Pyrite is the most abundant metallic mineral, and with it are associated, in certain of the 
ores, sphalerite (zinc-blende), galena, and chalcopyrite. In the oxidized veinstones 
limouitic products derived from the decomposition of pyrite are abundant, and black 
oxides of manganese are conspicuous where the parent vein-filling contains manganiferous 
calcite. 

Noil-metallic Minerals. 

Quartz. — Quartz, the commonest mineral of the veinstones, occurs in a great many 
forms, as the descriptions of the veins of the different mines will show. It varies from 
coarsely crystalUne to finely crystalhne and almost chalcedonic. The finely crystalUne 
varieties predominate. Platy quartz, pseudomorphous after calcite, is widespread through- 
out the mines of the southern portion of the subdivision. The rhombohedral form is 
here often perfect ; again, it can be ascertained only by microscopic observation. 
Mere rhombohedral shells of quartz with their interiors lined by drusy quartz are 
common. 

Amorphous and Cryptocrystalline Silica. — Jasper and chalcedony, forming veinlets 
and nests, are of widespread occurrence, especially in the rhyohtic lavas and breccias. 
The jasper is red, crimson, yellow, or more rarely ohve-green, in colour. The 
chalcedony is generally bluish-white or translucent, and is occasionally banded. Silicified 
wood is frequently found within the rhyohtic tuffs. Some of this has luidergonc carbon- 
ation prior to sihcification. Gem opal of rather poor quality is found sparsely distri- 
buted in a siUcified glassy rhyolite on Laycock's farm, Tairua. Small nests of it are 
also seen in dykes of rhj^ohte in various locahties. Common opal occurring mider similar 
conditions is more abundant. 

Calcite. — Calcite is, next t? quartz, the commonest vein-mineral, and almost com- 
pletely fills certain fissures. It occurs generally throughout the subdivision, and is 
especially conspicuous in the veins of AVaihi, Golden Cross, Maratoto, and Komata. 
Much of the calcite is not pure, but contains some manganese-carbonate and a small 
percentage of magnesiima-carbonate (see analyses, pages 106, 133). 

Epsomite. — Epsomite, the sulphate of magnesium, may be seen as small sparkHng 
stalactites in many disused drives. It is a product of the alteration of the wall-rocV 
rather than of the veinstone. 



49 

(■i.) INTRUSIVE ROCKS OF VARIOUS PERIODS. 

General Statement. 

Intrusive igneous rocks referable to the several periods of Tertiary vulcanism have 
development in the subdivision. Owing to the general similarity between the intrusive 
and the intruded rocks, it is often impossible to recognize the relationship of the rock- 
masses in the field, let alone to map the boundaries of the intrusions. 

In the maps accompanying this report the intrusives indicated arc all of andesitic 
type, and are, in the main, the youngest igneous rocks in the whole complex, breaking 
through even the " Third Period " rhyolitcs. As will be noted from the detailed descrip- 
tion of mining areas, the more productive part of the Waihi Goldfield is connected with 
an intrusive dacitic mass referable to the " First Period." Again, much of the " Tliird 
Period " massive rhyolite obviously breaks through rhyolitic tuft's and breccias, but this 
and similar occurrences are not considered under this section. 

Distribution and Pptrvhx/ij. 

The eastern portion of the conspicuous dyke fonning Table Mountain, described in 
the Thames (No. 10) Bulletin, falls within the area. So also do certain neighbouring 
isolated but evidently related intrusive masses. Tliis great dyke, which consists of a 
glassy porphyritic hypersthene-andesite. intersects the " Second Period " andesites and the 
Pliocene rhyolitcs. 

In the lower course of Billy-goat Creek a small belt of glassy hypersthene-andesite 
containing a Uttle quartz probably represents a southerly continuation of the Table 
Mountain dyke. A rock very similar, but containing a little hornblende, forms a small 
isolated ridge near Oxley's Gully, just south of Tairua Harbour. 

A densely wooded plateau-like range, separating the VVharekawa watershed from the 
headwaters of Stony and Ti-tree creeks draining to the Tairua, is a striking feature of 
the landscape. In the main, tliis consists of an intrusive belt of black glassy aphanitic 
pyroxene-andesite, in places resembhng a baked slate or, again, a tine-grained grauwacke. 
It is certainly intrusive into the Pliocene rhyoUtes, and the agencies of denudation have 
not yet succeeded in greatly modifying its original form, or in removing from the walls 
of the dyke the softer rhyolitcs which it protects. 

Within the valley of the Omahu Stream, a tributary of the Thames River, an 
irregularly shaped nuiss of hyalopilitic (glassy) hypersthene-andesite occurs. Tliis is also 
intrusive into rhyoUtes, and is involved in the structure of the eastern part of the 
conspicuous Omahu Peak. 

The Black Hill (elevation, 739 ft.), rising abruptly from the Waihi Plain, is evidently 
an intrusive mass, but its relationship to the rhyolitic rocks which skirt it upon three 
sides is obscure. The rock, wliich in places exhibits a nuirkedly columnar structure, is 
a hyalopihtic (glassy) hornblende-hypersthene andesite. 

Along the eastern coast-line, particularly southward of Homunga Bay, narrow intru- 
sive belts of black glassy andesites are noticeable here and there, certain of them 
intersecting tufaceous rhyohtes. These, however, are too small to be indicated upon the 
general maps. 

Pleistocene and Recent Deposits. 

The Pleistocene and Recent deposits may be grouped according to origin as — 
(a) fiuviatile, (6) fluvio-marine and marine, (c) a-ohan, and {d) talus. 

(a.) The fiuviatile deposits constitute the flood-plains of the lower and middle 
courses of the principal streams, and afford by far the greater part of the arable land of 
the subdivision. The mineralogical nature of the alluvium is, of course, determined by 
the character of the rocks occurring within the valleys of the several streams. 

4— Waihi-Tairua. 



52 



CHAPTER V. 



MINEEAL VEINS, AND CONDITIONS IN MINERALIZED AREAS. 



Page 
32 
52 
53 



Periods of Mineralization 

The Vein Fissures 

The Mineralizing Agents 

Rock-alteration connected with Mineral- 
ization . . . . . . . . 54 

Mineralogy of the \'ein-material . . 56 

Non-metallic Minerals . . . . 56 

Metallic Minerals . . . . . . 58 

Types of Jlineral Deposits and Structure 

of the ^'ein-material . . . . 00 

Sinter-deposits . . . . . . 61 



Page 

Oxidation . . . . . . . . 62 

The Ore-deposits . . . . . . 62 

(a.) Major Structural Features . . 63 
[b.) The Nature of the Rock enclosing 

the Veins . . . . . . 63 

(c.) Minor Structural Features . . 04 

(d. } Depth . . . . . . 64 

Underground Temperatures . . . . 6* 

Underground Gases . . . . . . 67 

Underground Water . . . . . . 67 



Periods of Mixeralizatiox. 
Within the Waihi-Tairua Subdi\'ision qusjrtz veins occur in the volcanics of each 
of the three periods of Tertiary \'tilcaiiistti, but it is probable that the payably metal- 
hferous veins are referable to the hydrotherinal acti\'ity which followed the extrusion 
of the rocks of the " First Period " and of the " Third Period." 

To the " First Period '' mineralization belong the veins of Waihi, Owharoa, Waite- 
katiri, Komata, and Maratoto. At Waihi the vein-bearing rocks are directly overlain 
by andesites of the " Second Period " and rhyohtes of the " Third Period," but into 
these rocks the veins have no extension. To the " Third Period " mineraUzation belong 
the veins of Broken Hills and Neavesv-ille in the Tairua watershed, of Ohui, Luck-at- 
Last (A\Tiarekawa), Kapowai (Gum town), and Waihi Beach. Within the rhyohtes of the 
■ Third Period," moreover, sihcified bands, mineralized pipes, and sihceous sinters abound 
at Pakirarahi Moimtain and in other places. 

In certain locaUties within the . Tairua and ^^'hangamata watersheds and elsewhere 
the andesites of the " Second Period " enclose quartz veins and sinter-deposits. Some 
of the veins have afforded a limited amoimt of gold-silver ore, but there is considerable 
evidence that metalhzation here followed the extrusioji of the " Third Period " rhyohtes 
which exist in the neighbourhood. 

The Vein Fissures. 

The numerous veins occurring throughout the volcanic complex imply a widespread 
fracturing and fissuring of the rocks. Through fissures so formed operated the mineraUzing 
agencies which have effected rock-alteration, deposition of veinstone in open spaces, 
and veinstone replacements of wall-rock. 

Rock-fracturing, although widespread, appears on the whole to have been productive 
of few well-defined persistent fissiires. The Maratoto reef, traceable for two miles ; the 
Waitekauri-Jubilee reef, traceable for over 50 chains ; and the Martha-Edward lode 
(Waihi), proven for 76 chains, probably represent the -most persistent vein fissures yet 
located. The great majority of the veins are connected with fractures of relatively 
minor strength, or with local sheeted or brecciated zones. 

In a previous report one of the writers * has drawn attention to the general 
uniformity in strike — a little to the eastward of the meridional hne — exhibited by most 
of the veins in the Thames Subdivision. This fact is equally noteworthy in the area 
now tmder review. It is thought that this unifonnity in the direction of fissuring has 
originated from a common cause, which has operated through various periods. It is 



Bull. No. 10 (New Series), C. Fraser, pp. 33-4. 



49 

(4.) INTRUSIVE ROCKS OF VARIOUS PERIODS. 

General Statement. 

Intrusive igneous rocks referable to the several periods of Tertiary vulcaiiism have 
development in the subdivision. Owing to the general similarity between the intrusive 
and the intruded rocks, it is often impossible to recognize the relationship of the rock- 
masses in the field, let alone to map the boundaries of the intrusions. 

In the maps accompanying this report the intrusives indicated are all of andesitic 
type, and are, in the main, the youngest igneous rocks in the whollo complex, brealdng 
through even the " Third Period " rhyohtes. As will be noted from the detailed descrip- 
tion of mining areas, the more productive part of the Waihi Goldficld is connected with 
an intrusive dacitic mass referable to the " First Period." Again, much of the " Third 
Period " massive rhyohte obviously breaks through rhyohtic tuffs and breccias, but this 
and similar occurrences are not considered under this section. 

Distribution and Petrolot/i/. 

The eastern portion of the conspicuous dyke forming Table Mountain, described in 
the Thames (No. 10) Bulletin, falls within the area. So also do certain neighbouring 
isolated but evidently related intinisive masses. This great dyke, wliich consists of a 
glassy porphyritic hypersthene-andesite. interaei ts the " Second Period "' andesites and the 
Phocene rhyolites. 

In the lower course of Billy-goat Creek a small belt of glassy hypersthene-andesite 
containing a Httle quartz probably represents a southerly continuation of the Table 
Mountain dyke. A rock very similar, but containing a little hornlilonde. forms a .small 
isolated ridge near Oxley's Gully, just south of Tairua Harbour. 

A densely wooded plateau-like range, separating the Wharekawa \vat( islud from the 
headwaters of Stony and Ti-tree creeks draining to the Tairua, is a striking feature of 
the landscape. In the main, this consists of an intrusive belt of black glassy aphanitic 
pyroxenc-andesitc. in places resembling a baked slate or, again, a fine-grained grauwacke. 
It is certainly intrusive into the Phocene rhyohtes. and the agencies of denudation have 
not yet succeeded in greatly moflifying its original form, or in removing from the walls 
of the dyke the softer rhyolites wliich it protects. 

Witliin the valley of the Omahu Stream, a tributary of the Thames River, an 
irregularly shaped mass of hyalopihtic (glassy) hypersthene-andesite occurs. This is also 
intrusive into rhyohtes, and is involved in the structure of the eastern part of the 
conspicuous Omahu Peak. 

The Black Hill (elevation, 739 ft.), rising abruptly from the WaiJii Plain, is evidently 
an intrusive mass, but its relationship to the rhyohtic rocks which skirt it upon three 
sides is obscure. The rock, which in places exhibits a markedly columnar structure, is 
a hyalopihtic (glassy) homblende-hypersthene andesite. 

Along the eastern coast-line, particularly southward of Homunga Bay, narrow intru- 
sive belts of black glassy andesites are noticeable here and there, certain of them 
intersecting tufaceous rhyohtes. These, however, are too small to be indicated upon the 
general maps. 

Pleistocene and Recent Deposits. 

The Pleistocene and Recent deposits may be grouped according to origin as — 
(a) fluviatile, (b) fluvio-marine and marine, (c) a;oli.an, and (d) talus. 

(a.) The fluviatile deposits constitute the flood-plains of the lower and middle 
courses of the principal streams, and aflord by far the greater part of the arable land of 
the subdivision. The mineralogical nature of the alluvium is, of course, determined by 
the character of the rocks occurring within the valleys of the several streams. 

4 — Waihi-Tairua, 



52 



CHAPTER V. 



MINERAL VEINS, AND CONDITIONS IN MINERALIZED AREAS. 



Periods of Mineralization 

The Vein Fissures 

The Jlineralizing Agents 

Rock-alteration connected with ilineral 

ization 
Mineralogy of the Vein-material 

Non-metallic Minerals 

Metallic Minerals . . 
Types of Mineral Deposits and Structure 

of the Vein-material 
Sinter-deposits 



Page 
52 
,52 
53 

54 
5() 
56 
58 

60 
61 



Page 

Oxidation . . . . . . . . 62 

The Ore-deposits . . . . . . 62 

(«.) Major Structural Features . . 63 
(b.) The Nature of the Rock enclosing 

the \'eins . . . . . . 63 

(c.) Minor Structural Features .. 64 

{d. ) Depth . . . . . . 64 

Underground Temperatures . . . . 66 

Underground Gases . . . . . . 67 

Underground Water . . . . . . 67 



Periods of Mineralization. 
Within the Waihi-Tairua Subdi\'isiou quartz veins occur in the volcanics of each 
of the three periods of Tertiary vulcanism, but it is probable that the payably metal- 
hferous veins are referable to the hydrothermal acti^^ty Avhich followed the extrusion 
of the rocks of the " First Period " and of the " Third Period." 

To the " First Period '' mineralization belong the veins of Waihi, Owharoa, Waite- 
kauri, Komata, and Maratoto. At Waihi the vein-bearing rocks are directly overlain 
by andesites of the " Second Period " and rhyohtes of the " Tliird Period," but into 
these rocks the veins have no extension. To the " Third Period " mineralization belong 
the veins of Broken Hills and Neavesville in the Tairua ^yatershed, of Ohui, Luck-at- 
Last (Wharekawa), Kapowai (Gumtown), and Waihi Beach. Within the rhyohtes of the 
" Third Period," moreover, silicified bands, mineraUzed pipes, and sihceous sinters abound 
at Pakirarahi Mountain and in other places. 

In certain localities within the Tairua and ^\^langamata watersheds and elsewhere 
the andesites of the " Second Period " enclose quartz veins and sinter-deposits. Some 
of the veins have afforded a limited amount of gold-silver ore, but there is considerable 
evidence that metalhzation here followed the extrusion of the " Third Period " rhyolites 
which exist in the neighbourhood. 

The Vein Fissures. 

The numerous veins occurring throughout the volcanic complex imply a widespread 
fracturing and fissuring of the rocks. Through fissures so formed operated the minerahzing 
agencies which have efiected rock-alteration, deposition of veinstone in open spaces, 
and veinstone replacements of wall-rock. 

Rock-fracturing, although widespread, appears on the whole to have been productive 
of few well-defined persistent fissures. The Maratoto reef, traceable for two miles ; the 
Waitekauri-Jubilee reef, traceable for over 50 chains ; and the Martha-Edward lode 
(Waihi), proven for 76 chains, probably represent the most persistent vein fissures yet 
located. The great majority of the veins are connected with fractures of relatively 
minor strength, or with local sheeted or brecciated zones. 

In a previous report one of the writers * has drawn attention to the general 
imiformity in strike — a little to the eastward of the meridional line — exhibited by most 
of the veins in the Thames Subdivision. This fact is equally noteworthy in the area 
now imder review. It is thought that this uniformity in the direction of fissuring has 
originated from a common cause, which has operated through various periods. It is 



* Bull. No. 10 (New Series), C. Eraser, pp. 33-4. 



51 

At Waihi the marked depression which the land-muss has imdergone will be apparent 
from the detailed descriptions of the geological structure of the mining portion of the 
field. The isolated occurrences of raised beaches at Orokawa Bay and Waihi Beach, 
mentioned on previous pages, register only a recent and very minor elevation. 

" The dislocation of rock-masses by faulting has been shown by the mining opera- 
tions of almost every locaUty to be a common feature. Owing to the comparative 
homogeneity of the enclosing rocks, and their proneness to weathering, the existence of 
few of these faults, however, can be inferred merely from an examination of the surface. 
The origin of faulting in an area which gives evidence of widespread earth-movements, 
and which has been the scene of intense volcanic activity at several different periods in 
the Tertiary era, is not far to seek. Upward and lateral thrusts of the crust, due to 
violent migration of rock magma, can be postulated ; so also can subsidences, due to the 
weakening of the basement following the transference of great quantities of material from 
considerable depths to the surface by volcanic agencies. Reversed or thrust-faults and 
normal or tension-faults are thus explainable, and occur frequently." 

In the Waihi and Waihi Grand Junction mines faulting effecting dislocation of 
the veins is by no means as common as in most of the other mining centres of the 
peninsula. The more recent developmental work in the eastern and south-eastern 
portions of the latter property has, however, determined the existence of a fairly 
persistent line of faulting, or structural weakness. 

The Karangahake Gorge, occurring just to the southward of the subdivision, where 
the waters of the Ohinemuri River have broken through the main backbone range of the 
peninsula to the western seaboard, has often been regarded as cut along a plane of weak- 
ness — probably a fault-line. Although the topographic expression of the country is 
suggestive of the existence of a great fault in this locahty, further geological evidence 
is required to settle the question definitely. In the neighbouring Waitawheta tributary, 
quartz veins having an appreciable dip cross, without displacement, the narrow deep gorge 
cut by the stream, so that here at least no faulting later than the formation of the 
vein fissures has occurred. 

The Firth of Thames, with its former prolongation — now the low-lying plains of the 
Thames Valley — is apparently a graben or down-faulted area. Both the Moanataiari 
Fault and Beach Shde, near the Thames foreshore, are believecj to be dislocations 
connected with its formation.* Regarding the southern prolongation of this graben, 
Lindgren writes, " At Te Aroha, near the southern end of the range, its existence is 
clearly indicated by the topography of the scarp, by the narrow and picturesque gorge 
which the Ohinemuri River has cut through it, and by the capture of much drainage 
belonging to the eastern part of the peninsula." f 

While strongly beUeving in the existence of the Thames Valley graben, the writers 
regard the locality of the gorge of the Ohinemuri as too far back from the probable 
fault-Une to have been materially affected by this downthrow. With Park and others, 
they prefer to ascribe the reversal in drainage through this gorge to the ponding of the 
Ohinemuri Valley by the volcanic extrusions of PUocene times in the vicinity of the 
eastern coast-hne. 

♦See Bulletin No. 10, Thames Subdivi-sion, pp. 31-32. 
fEng. & Min. Journ. (New York), 2nd Feb., 1905. 



4 ♦ — Waihi-Tairua. 



50 

The most extensive of the river-flats on the eastern side of the main water-parting 
are those associated with the larger streams draining into the ^Vhitianga Estuary, and 
those forming the open valley-beds of certain reaches of the Tairua, Wharekawa, and 
Whareldrauponga rivers. On the western side the valleys of the lower portions of the 
Hikutaia, Komata, and Ohinemuri afford larger stretches of alluvial land. The alluvium 
of the Ohinemuri coalesces with that of the Thames-Hauraki plain, which extends for 
many miles westward of the subdivision. The deposits of the swamps which occur 
here and there throughout the subdivision, and particularly in connection with low- 
lying rhyohtic country, may, in the main, be grouped under this heading. 

River-terraces are not conspicuous in tliis subdivision, as regional movements of 
depression rather than of elevation appear to have predominated throughout late 
Tertiary times. 

(b.) The fluvio-marine and marine deposits worthy of mention comprise the tidal 
mud-fiats of the estuaries of the larger streams debouching upon the eastern coast-line, 
and also the marginal beach deposits. 

The more extensive beaches are the Ohui-Wharekawa, the Ramarama-Whiritoa, the 
Mataora, the Orokawa, and the Waihi-Bowentown, all of which are indicated on the maps. 
Raised beaches are not common. The most conspicuous are those forming the terraces at 
Orokawa Bay; and here also, it may be mentioned, rock-ledges elevated several feet above 
the high-water mark are recognizable. 

(c.) iEohan or wind-blown deposits — sand-dunes — occur in the rear of most of the 
exposed beaches of the eastern coast-Une, forming himimocky sandy country extending 
for some chains inland. A considerable portion of the sandy and loamy rhyohtic debris, 
largely pumiceous, which is found on the Waihi Plain, or even on the lower more gentlv 
sloping flanks of the bordering hills, is mainly of asohan origin. 

(d.) The debris coming under the heading of "talus" is mostly confined to isolated 
landshps and to the loose angular rock - fragments gravitating from steep country. 
Regular talus slopes, however, such as are met with in the alpine country of southern 
New Zealand, are altogether absent. 

Regional Earth-movements and Faulting. 

As regional earth-movements and faulting have affected not only the Waihi-Tairua 
Subdivision, but the whole Hauraki land-mass, the statements made in the Thames 
Bulletin (No. 10), page 30, are equally apphcable here : — 

" An inspection of a geological map covering the whole Hauraki Division will show 
that to the north and west the basement sedimentaries have their greatest development, 
and then follow to the east and south, in order of age, the three series of Tertiary 
volcanics. As might be expected, outlying areas of the older Tertiary igneous rocks 
surrounded by the younger rocks do occur, but the statement regarding the general 
disposition still holds good. The disposition of the rock-masses as a whole, and of the 
members of certain of the individual series, registers a tilting movement of the whole 
Hauraki land-mass on a north-east axial line connecting Rocky Point on the western 
coast-Une with Kuaotunu on the eastern coast-hne. The area north-west of this line 
has undergone elevation ; the area to the south-east, depression. The basement sedi- 
mentary rocks are not visible south of this Rocky Point - Kuaotunu hne. This com- 
pensating movement of elevation in one part of the area and depression in another 
appears to have begun in an early Tertiary period, and has certainly continued to 
comparatively recent times, if, indeed, it is not still in progress. Raised sea-beaches 
are common on the north-western coast-hne ; sunken-river mouths, cut in the PUocene 
rhyohtes, are conspicuous on the south-eastern coast-hne." 



55 

ficatioii through the ageucy of contained solutions of gases rich in carbon-dioxide, which 
is such a characteristic product of volcanic action." In many areas in the subdivision 
where vein fissures are absent, or at least not observable, the rocks are extensively 
chloritized, but not propyhtized ; and it may be stated generally that rocks showing, on 
microscopic examination, no chloritization are almost unobtainable. Where the fissure 
solutions were high in carbonates, however, as they undoubtedly were at certain stages 
of vein-formation at Waihi and elsewhere, it is Ukely that chloritization also represented 
a stage in the propylitizaticn of the wall-rock. 

In vein-bearing areas gradation from the sUghtly altered (chloritized) bluish-black 
andesite or dacite through the more pronounced chloritic or (jriinstein stage to the hght- 
coloured granular pyritous propyhte is in places apparent, but ideal sections are by no 
means as common as might be expected. Though generally the more propyhtized rocks 
occur in the vicinity of the vein fissures, in places this is not the case. Thus the south- 
east crosscut, No. 8 level, Waihi Mine, exposes in passing from the foot- wall of the 
Royal lode hard dark shghtly chloritized dacite, chloritized dacite ((jriinstein), siUcihed 
propyhte, and normal propyhte. Such occuirences, however, are but analogous to the 
" hard bars " or " floaters " of the Thames mines, and to the cores of fairly fresh 
andesite or dacite found inset in masses of highly altered rock (spheroidal alteration). 
These emphasize the diversity of the circulation of waters through the rock-masses. 

Sihcification of the propyhtes, especially in the vicinity of the veins, is of very 
common occurrence, the rock in the most advanced stage often resembhng a pyritized 
chert. The more particular case of replacement of the propyhte by sihceous ore-bearing 
solutions is described at length in connection with certain types of the Waihi ore. 

Analyses of various specimens of the altered and partially altered dacites of the 
Waihi field will be found in the chapter deahng with " General Geology," page 42. A 
" series of analyses of specimens from a crosscut to the Empire vein, Waihi Mine," made 
by Finlayson, " shows the extensive replacement and sihcification of the rocks " : — 





(1.) 
Per Cent. 


(2.) 
Per Cent. 


(3.) 
Per Cent. 


(4.) 
Per Cent. 


(5.) 
Per Cent. 


(6.) 
Per Cent 


SiO, . . 


.. 63-45 


58-39 


61-78 


69-35 


76-61 


85-65 


Al,03 •• 


.. 15-26 


16-51 


14-89 


11-66 


8-31 


1-35 


Fe,03 .. 


. . 2-28 


2-46 


2-08 


1-53 


1-08 


0-43 


FeO .. 


. . 3-01 


2-98 


2-51 


1-66 


0-59 


0-21 


MgO .. 


. . 1-29 


1-66 


108 


0-46 


0-51 


0-31 


CaO .. 


. . 3-44 


4-08 


3-16 


2-09 


3-61 


2-56 


Na,0 .. 


.. 2-21 


2-08 


2-18 


1-06 


0-29 


0-28 


KjO .. 


.. 1-78 


2-89 


3-68 


3-31 


1-98 


1-41 


n,o-.. 


.. 110 


2-41 


1-89 


1-61 


0-43 


0-24 


H,0-H .. 


. . 2-90 


2-87 


3-05 


2-12 


1-08 


1-33 


TiO, . . 


. . 0-75 


0-68 


0-69 


0-43 


0-28 


Trace. 


CO2 .. 


.. 1-08 


1-56 


2-01 


2-24 


1-87 


204 


P,0, .. 


. . 0-29 


0-31 


0-30 


0-26 


0-11 


Truce. 


MnO .. 


. . 0-36 


0-32 


0-28 


Oil 


Oil 


0-12 


FeSa •• 


•- 




0-65 


1-88 


3-59 


4-69 



Totah . 99-20 99-20 100-23 99-77 100-45 100-62 

(1.) Fresh hornblende-dacite, Waihi. 

(2.) Chloritized hornblende-dacite, 45 ft. from Empire vein. 

(3.) Altered dacite, 30 ft. from Empire vein, 850 ft. level. 

(4.) Altered dacite, 15 ft. from Empire vein, 850 It. level. 

(5.) Altered dacite, adjoining Empire vein, 850 ft. level. 

(6.) Replacement ore, Empire vein, 850 ft. level. 



64 

audesites or dacites ; while those of Waihi Beach are rhyobtes. One can only conclude 
that waters which rose from an unknown source through strong deep-seated fissure^ 
supphed the carbonates in question. 

The bydrothermal action — periods of solfatarism — were evidently in great part the 
" eruptive after-actions " which marked the closing phases of periods of vulcanism. At 
Waihi, however, it would appear that a time-interval, sufficiently long for a considerable 
amount of erosion to have been effected, supervened between the intrusion of the dacitic 
boss and the formation of the vein fissures which it encloses. The fact that important 
metallization appears to have attended the hydrothermal action referable to the " First 
and " Third " periods of vulcanism, and was absent from that of the " Second Period," 
is an argument for the magmatic origin of the ore-bearing solutions and the existence 
of fairly definite metallo -genetic epochs. 

Rock-alteration connected with Mineralization. 

In the Waihi-Tairua Subdivision, as in all other andesitic goldfields, rock-alteration due to 
hydrothermal action is a characteristic feature, more especially in the vicinity of the reefs. 

The alteration of the various rocks — andesites, dacites, and rhyoHtes — differs in degree 
more than in character. In places the several types of andesites and dacites where 
highly altered are, in the field, quite indistinguishable from one another. In this bulletin, 
as in previous pubUcations, the writers have hmited the term " propyhte " (as defined 
by Rosenbusch) to the altered andesites and dacites, the rhyohtes affected by hydro- 
thermal action being described as "altered." 

The characteristic imoxidized propyhte is a grepsh-white or greenish-grey only moderately 
hard rock, granular in appearance, and almost always containing pyrite. A microscopic 
examination of the propyhte reveals the fact that the feldspars are more or less changed 
to a mixture of carbonates and sericite, with frequently secondary quartz. The ferro- 
magnesian minerals are, to a greater or less degree, altered to carbonate, magnetite, 
pyrite, and sometimes quartz. Pyrite is abundantly scattered throughout the rock, in many 
places replacing original magnetite or ferro-magnesian constituents. Valencianite with low 
polarization-colours is present as a secondary product in the altered Waihi dacites, appearing 
as pseudomorphs after the hme-soda feldspars, and as ramifications and partial replacements 
of the original crystals. The mineral was isolated and analysed by Finlayson,* wath the 
following result : — 

ler Cent. 
SiUca (SiOj) . . . . . . . . . . . . 65.85 

Alumina (AI2O3) .. .. .. .. .. .. 1848 

Potash (K2O) .. .. .. .. .. .. 11-25 

Soda (Na^O) .. .. .. .. .. .. 4-11 

Sp. gr., 2-61. 

99-69 

Leucoxene is a frequent pseudomoi-phous product after titaniferous magnetite, but, 
as remarked by Finlayson, siderite (or probably some other iron-bearing carbonate) has 
in the past frequently been mistaken for ttiis mineral. 

The chloritic type, or griinstein facies, of alteration is regarded by many authorities 
as the initial stage in the process of propyhtization, the solutions gradually altering their 
composition as they migrate laterally from the fissures. In this the ferro-magnesian 
minerals are more or less replaced by fibrous green chlorite, but the feldspars remain 
fresh, or are only partly altered to carbonates and sericite. There is considerable evi- 
dence for the view taken by Finlayson, after a detailed examination of two series of 
Hauraki rocks, that chloritization is an earher and widespread process of rock-alteration 
" which took place immediately after the eruption of the rocks and during their sohdi- 



* Economic Geol., voL 4, No. 7, pp. 632-45. 



58 



This material contains almost all the constituents of the propyhtized dacite, except hme, 
which has been completely leached. It consists mainly of an impure kaohnite and sihca. 
Somewhat similar clays are common in the veins enclosed in rhyohtcs at Tairua. A 
sample from the Golden Hills Claim, No. 2 level, which, however, contained gritty material, 
gave the following analysis : — 

Per Cent. 
4948 



Alumina (AljOg) 










32-68 


Ferric oxide (FcjOa) 








. ' 


. 0-72 


Manganous oxide (MnO) 










. 0-05 


Lime (CaO) 










Nil. 


Magnesia (MgO) 










0-30 


Potash (KjO) 










810 


Soda (Na^O) 










0-20 


Moisture at 100° C. . . 










2-81 


Combined water and organic 


matter . 








5-30 



99-64 
Note. — This sample contained ITdwt. 15 gr. of gold and 4dvvt. 10 gr. of silver per ton. 

Silica. — Almost indistinguishable megascopically from the white powdery aggregates, 
clays, and waxy scales already mentioned is a material which proves on analysis to 
be almost entirely sihca. A sample collected from the Royal lode. No. 4 level, Waihi 
Mine, gave on analysis : — 

Per Cent. 



Sihca (SiOj) 










98-70 


Alumina (AI2O3) 










0-70 


Iron-oxide (FeoOj) 










0-35 


Lime (CaO) 










0-05 


Magnesia (MgO) 










Nil. 


Alkahes . . 










Nil. 


Moisture at 100° C. 










0-12 


Combined water and organic 


: matter. 








0-34 



100-26 

This is practically the same as the "sihca," regarded as a very fair "indicator" for gold, 
at the Thames. 

Metallic Minerals. 

Gold and Silver. — The two precious metals, except in the few locahties where tellurides 
occur (also see " Selenides "), are found alloyed as an electrum, the ratio of the two metals 
in the alloy varying greatly. The gold-fineness of the electrum from the ore of the 
Waihi Mine is 0-645. 

The electrum is found in the veinstones of the subdivision either in a very fine 
state of division enclosed in the various sulphides, or sparsely disseminated throughout 
the oxidized ore. More rarely it exists as scales, wires, or in granular aggregates visible 
to the unaided eye. Native silver has occasionally been seen in the Waihi Mine. 

Tellurides of Gold and Silver. — Tellurides of gold and silver occur in the Silverstream, 
Old Maratoto, and other mines at Maratoto. These consist mainly of hessite, with 
probably some admixture of petzite. Hessite was identified in small amount in the rich 
ore mined in the upper workings of the Union-Silverton section of the Waihi Mine. 
Analyses of the ore of the Martha workings have failed to reveal the presence of 
tellurium. 



69 

Selenidcs. — The bullion derived from the cyauidatioii of Waihi ores contains 
appreciable quantities of selenium. Bullion from Maratoto was also found to contain 
the same element.* No definite selenium mineral has, however, yet been identified 
in the ore. The selenimn probably replaces part of the sulphur in argentite, and 
it is even possible from the analogous properties of selenium and tellurium that the 
former may also form a compound with gold. 

Argentite (Silver Glance). — Argentite, the sulphide of silver, generally lu finely 
granular forms, occurs throughout the sulphide ores of Waihi, Golden Cross, Maratoto, 
Komata, and Whangamata. Arborescent forms, and also perfect cubical crystals up to 
0-2 in. in diameter, were occasionally noticed in the Waihi Mine. 

Pyrargyrite (Ruby Silver), the sulphide of antimony and silver, has been detected as 
small crystals in cleavages or vugs in some of the richer veinstone in both the Waihi and 
the Waihi Grand Jmiction mines. 

Proustite. — This sulphide of arsenic and silver occurs under similar conditions to 
pyrargyrite. 

Cinnabar, the sulphide of mercury, is the principal ore mineral in the Ascot 
Mine, Mackaytown, and occurs in association with sihceous sinters. The mineral is 
also sparsely found in alluvium in several creeks of the subdivision, notably in Tangatara 
Creek, Wharekawa, in the largest stream entering Homunga Bay, and in Edmonds 
Creek, Wharekirauponga. In every case apparently this detritus is shed from very 
small veinlets occurring in rhyoUtic rocks. 

Pyrite. — Pyrite, the disulphide of iron, is the metalhc mineral of widest distribution 
ill the veins and in the altered rock. It is found in cubes, pyritohedrons, and also 
in the massive and granular forms. 

Marcasite, or White Iron-pyrites. — This mineral, differing httle in appearance from 
ordinary pynte, but imdergoing decomposition much more rapidly, occurs to a much 
less extent than pyrite. 

Mclantcrite (Green Vitriol), the sulphate of iron, as a secondary product, may 
frequently be seen in the warm old mine-workings where pyrite is undergoing oxidation. 
It often contains some magnesia-sulphate and alum, and in places traces of copper. 

Mispickel, or Arsenofyrite. — This mineral, arsenical iron-pyrites, is occasionally 
found in the Waihi and Waitekauri ores. 

Chalcopyrite, the sulphide of iron and copper, is fairly common in the sulphide 
ore of the mines at Waihi and Waitekauri, and is occasionally seen elsewhere. 

Chalcanthite (Blue Vitriol), sulphate of copper, is found with melanterite and 
aUied minerals in old mine-workings. It results from the decomposition of chalcopyrite. 

Malachite (Green Carbonate of Copper). — Stains of this mineral are noticeable in the 
oxidized ores of Waihi, Waitekauri, and elsewhere where chalcopyrite occurs. 

Azurite (Blue Carbonate of Copper) occurs under the same conditions as malachite, 
but is less common. 

Galena, the sulpiride of lead, is found in a finely granular form in the sulphide ore 
at Waihi and Waitekauri. 

Sphalerite, Black Jack, or Zinc-blende is commonly associated with other sulphides 
in the Waihi, Waitekauri, and other ores. It occurs in massive platy and also finely 
crystalhne forms, and as an amorphous black powder. 

Rhodocrosite, the carbonate of manganese, is noticeable in the veinstone of many 
locahties, more especially at AVaihi and at Waihi Beach. Large rhombohcdral crystals 
of rhodocrosite have been obtained from vugs in the veinstone of the Wailii Grand 
Jimction Mine. 

* Report by Alex. Montgomery, Mines Rep., 1889. C.-2, p. 20. 



63 

In most of the mines the shoots worked were disposed at high angles within the 
plane of the veins, and their pitch-lengths usually exceeded their stope-lengths. Several 
shoots, separated by unprofitable or barren veinstone, have in cases been found to occur 
along the course of a lode. 

Factors which have had considerable influence upon the locahzation of the ore- 
deposits are : {a.) Major structural features — the existence of intrusive rock-masses, 
crateriform structures, &c. (b.) The nature of the country rock enclosing the veins. 
(c.) Minor structural features — the dimensions of fissures, the existence of branching 
veins, intersecting veins, faults, cross-courses, &c. (d.) Depth. 

(a.) Major Structural Features. 

The intimate genetic connection of ore-shoots with intrusive rocks is a feature of 
many metaUiferous mining fields. In the area imder review the intrusive and intruded 
rocks of the andesitic complex — the main " auriferous series " — possess very similar 
mineralogical compositions, and it is therefore often difficult to determine the structure. 

A study of the Waihi Goldfield has led the writers to the conclusion that the more 
productive portion of this area lies wnthin a fairly large dacitic intrusion. Veins contain- 
ing ore-shoots have been developed in the surrounding bedded (flow) dacitfis as the result of 
the intrusion, but are of much less importance. 

At Lower Taima and at Whareldrauponga the veins are practically confined to 
intrusive masses of rhyolite in somewhat older tufaceous rhyolites or in andesites, and 
have Uttle extension beyond these intrusives. 

At Pakirarahi Mountain, the locus of the Golden Belt and Champion claims, it 
appears more than likely that an old crateral vent existed, and that the ore-veins and 
pipes and the siliceous sinters are deposits from the hydrothermal solutions which rose 
through this area of structural weakness. At Ohui, too, the veins of the Phoenix and 
neighbouring claims appear to be connected with an ancient rhyolitic crater wliich has 
broken through the andesites. 

In most of the claims wnthin the vein-bearing belt extending north-eastward from 
Owharoa to Maratoto the actual structure of the rock-mass could not be deciphered, 
from the limited extent of underground workings open. It is noticeable in certain 
portions of the Hauraki Peninsula, and particularly within the Coromandel Subdivision, 
that the groups of ore-bearing veins occur along north-easterly striking belts. This fact 
suggests the existence of major deep-seated fissures, from which were dispersed the 
impregnating mineral solutions. The Owharoa-Maratoto mineral belt is, however, coin- 
cident with a circumscribed narrow belt of the " First Period " volcanics, so that the 
analogy as regards disposition may be apparent rather than real. 

(b.) The Nature of the Rock enclosing the Veins. 

The fact that within a vein-bearing series the intrusive rocks constitute more 
favourable repositories for ores than the intruded rocks has, to some extent, reference to 
the nature of the country enclosing the veins. Even in a homogeneous rock-mass, how- 
ever, the phase of alteration exhibited by the rock has in many cases had an effect on 
ore-deposition in the fissures. The favourable or " kindly " coimtry of the miner is a 
completely propyhtized andesite or dacite, or highly altered rhyohte. It is of hght 
colour, fairly uniform texture, is moderately hard, and contains, where imoxidized, 
disseminated fine-grained pyrite having a splendent lustre. The greenish chloritized or 
partly altered rock is usually barren or poorly productive. In the strong veins of the 
Waihi Goldfield, however, patches of dacite, relatively little altered, occasionally form the 
actual vein-walls, and these appear to have exercised Uttle or no effect on the tenor of 
the ore. 



62 

In the old Waihi Monument Claim pyrite has been deposited in connection with the 
siliceous sinter to an unusual extent. A sample jaelded — iron 20-26 per cent, and 
sulphur 23-01 per cent ; corresponding, therefore, to the disulphide (FeSj). In this 
material, gold and silver exist to the extent of 9 gr. and 1 dwt. 12 gr. respectively per ton. 

Samples collected from various parts of the sinter-deposits in which occurs the 
cinnabar, at Mackaytown, were submitted for assay. The gold-silver content here was 
lower than in those samples already quoted. In most cases the assays showed only 
traces of gold-silver, or gave negative results. 

In the proximity of the ore-occurrences at Neavesville, Ohui, and other places, it is 
probable that the sinters represent the " spill " of the vein-forming solutions, but at the 
Silverton Hills, Waihi, and certain other locahties they appear to be of later origin than 
the veins in the neighbourhood. 

Oxidation. 

The extent to which oxidation has affected the veins varies greatly. In addition 
to the groimd-water level, the depth of which is largely dependent upon the topographv, 
the permeabihty of the veinstone and of the enclosing rocks, and the presence or 
absence of open fractures, and, occasionally, unconformity contacts, have been the 
main factors which have determined the vertical extent of the oxidation. At Waihi, 
throughout a considerable extent of the field, the yoimger barren volcanics capping the 
vein-bearing rocks have proved an effective barrier to oxidizing agencies. 

The existence of an old land-surface within the bedded dacites at Waihi, together 
with the seepage of surface-waters down the imconformity plane, has introduced a some- 
what unusual feature in the Waihi Mine. Here, in addition to the superficial zone of 
oxidation, a second zone of oxidized veinstone and foot-wall rock occurs in connection 
with the Martha lode, beneath a horizon showing httle or no oxidation. 

The most common and widespread effect of oxidation is, of course, the oxidation 
of pyrite, affording the rusty iron-oxides. Consolidated hmonitic gossans are imcommon ; 
the nearest approach to them appears at Waihi Beach. Carbonates of copper derived 
from chalcopyrite are seen in a few places. 

In the veins of the Waihi-Komata type the dissolution of manganiferous calcite 
results in the Uberation of considerable quantities of black oxides of manganese, which 
stain the quartz, and also segregate into cindery-looking bands. 

Impure clays and kaohnitic material, due mainly to the leaching of the wall-rock 
(perhaps only in part by vadose waters), are not imcommon in some of the vein-material. 

The proportion of gold to silver, owing to the greater solubiUty of the latter 
metal and its compounds, appears, on the whole, to be higher in the oxidized than in 
the deep-seated ores, but actual figures bearing on this point are not available. 

The enrichment of ores due to oxidation processes is discussed elsewhere in this 
report. 

The Ore-deposits. 

The payable gold-silver ores in the veins are generally disposed as shoots of variable 
extent and of more or less definite outhne. Most of the shoots exploited outcropped at 
the surface, or, as at Waihi, extended downward from the buried eroded caps, or from 
the original apices of the veins. Other shoots, as at Tairua Broken Hills, did not 
approach the surface or the caps of the veins. 

The lower limits of many of the shoots have been reached in mining development. 
The ore has generally been fomid to wedge out gradually like a flattened inverted cone. 
Again, the stope-lengths of the shoots have been fairly well maintained, though broken 
by barren patches ; and the pay-ore terminated gradually or abruptly along an undulating 
horizon. 



61 

(2.) To the second group of deposits are referable all the other mineral deposits 
of the subdi\asion. 

Subgroup (a) comprises the veins of the old Waitekauri and Jubilee claims, and 
most of those at the Maoriland Claim (Waitekauri), the Rising Sun veins (Owharoa), 
the various veins of the Auckland and Glamorgan claims (Whangamata), and of the 
Luck-at-Last Claim (WTiarekawa). These present the vuggy, comby, massive, and 
occasionally crustified structures usually associated with fissure-filling of crystalhnc 
quartz. In addition to pyrite, one or more of the following sulphides may be present : 
Sphalerite, galena, chalcopyrite. or argentite. 

Subgroup (b) is more particularly confined to the rhyohtes, and is well represented 
in the Tairua Broken Hills and other claims at Tairua, and in those of Whareldrauponga. 
In the Tairua Broken Hills sohd quartz, excepting as small parallel lenticular or 
ramifpng stringers of tiinty character, is almost absent, although the vein-material is 
in many cases confined to well-defined fissures. Sihcified bands or zones, fairly well 
defined, although showing no definite fissure-walls, are also conspicuous in these 
rhyohtic fields. Impure kaohnitic clays and " sihca " occur throughout the vein-material. 

The main ore-body of the Maoriland Claim, at Waitekauri, is associated with a 
fissure intersecting a bed of sihcified dacitic breccia, and may be included here. 

Subgroup (c) comprises many of the impregnation deposits of the Gumtown field, 
of the Champion and Golden Belt at Neavesville, and of the old Smile-df-Fortune 
Claim at Owharoa. In these localities masses of the altered rocks have been more 
or less generally impregnated with siliceous ore-bearing solutions, and enclose ramifvnng 
veinlets and geodic nests of quartz, and 'seams stained with iron-oxides. These deposits 
in places, however, grade into somewhat definite mineraUzed bands, pipes, or veins. 

Sinter-deposits. 

SiUceous sinters, the deposits of hydrothermal springs, are of widespread occurrence 
throughout the subdi\asion, and are usually confined to areas of rhyolitic or " Second 
Period " aiidesitic rocks. Many of the deposits are evidently of the mushroom type, 
and of superficial deposition ; others appear to have some persistence iii depth. A 
distinct stratification but httle removed from the horizontal is often noticeable in the 
superficial deposits. 

The sinter consists mainly of amorphous or cryptocrj'staUine silica, generally white 
in colour, but varj-ing to grey, red, yellow, brown, or even black. Here and there are 
enclosed small geodic nests and thin lenticular veinlets of crystaUine quartz. 

Pyrite and marcasite, with their o.xidation-products, not infrequently occur dis- 
seminated throughout the mass. 

An analysis of a general sample of the sinters capping the hills on the Phoenix Claim, 
Ohui, reads : — 

Per Cent. 
SiUca (SiOj) . . . . . . . . . . 97-50 

Ferric oxide (FejOj) . . . . . . . . . . 0-80 

Alumina (AUOa) . . . . . . . . . . U-83 

Lime (CaO) . . . . . . . . . . Nil. 

Magnesia (MgO) . . . . . . . . . . Nil. 

AlkaUes . . . . . . . . . . . . . . Nil. 

Sulphuric anhydride (SO 3) . . . . . . . . Nil. 

Moisture at 100° C. . . .. .. .. .. .. 0-12 

Combined water and organic matter . . . . . . 048 



99-73 
Assay — Gold, 7 gr. per ton ; silver, 8 gr. per ton. 



64 

At Komata, Waitekauri, Maratoto, and many other localities there is a marked 
deterioration or absence of pay-ore where the veins pass from the moderately hard 
propylite into soft shattered propylite or chloritized dacites, or where a heav'}' P^ggy 
selvage or crushed band separates the veinstone from the soUd propyUte. 

In a bedded complex the flow rocks, probably owing to differences in physical 
rather than in mineralogical character, constitute more productive vein-bearing country- 
than do the breccias. 

The pecuUar but not uncommon phenomenon designated by the miner as " ore to 
ore," or shoots " back to back," is well exhibited in the Tairua Hills Claim. Here 
north-south trending veins occur in massive rhyoUtc, and these carrj" their principal 
ore-shoots where they traverse an obliquely striking (north-east) belt. As, however, the 
rock within and immediately outside the Umits of this belt showf no appreciable change 
of character, these conditions must be due to some other factor than the influence of 
wall-rock or precipitation of the metals. It seems not unreasonable to suppose that 
there exists here a deep-seated cross-fissure, from which the impregnating ore-solutions 
have been dispersed throughout the various veins. 

The influence of certain of the wall-rocks as precipitants of sulphides will be apparent 
from subsequent description of the mines at Waihi and elsewhere. 

(c.) Minor Structural Features. 

Within an ore-shoot, high-grade ore is usually associated with the enlargements or 
wider portions of the vein, and veinstone of considerably lower tenor with the contrac- 
tions or " pinches." This feature is especially apparent at Waihi, and also at Komata. 
Evidently the uninterrupted passage of the mineraUzing solution has been favourable to 
precipitation. The locaUties where numerous branching veins are associated ^\^th the 
main ore-bodies — the zones of more pronounced rock-fracture — have usually proved 
especially productive. Since, however, these loop veins, " droppers," and spur veins are 
generally confined to the more superficial horizons, the proximity to the surface may 
here have been an important factor in effecting ore-deposition. 

Intersecting veins, faults, and cross-courses have in places influenced the locaUzation 
of ores in the veins of the Waihi-Tairua Subdivision. Ores of comparatively low and 
fairly imiform grade, however, rarely show the same dependence on minor structural 
features as do richer bonanza ores, and these locaUzation-factors have had far more 
effect in the Thames and Coromandel goldfields than in the area imder re%dew. 

At Waihi the occurrence of the most easterly shoot of ore on the Empire lode in 
the Grand Junction Mine is genetically connected with the main fault which here 
intersects the lode. The widest cross-section of ore in the Royal lode is also found in 
close proximity to the same fault-line. 

The nearest parallel in this subdivision to the " flinties " or " indicator " veins so 
common at Thames is seen in the Tairua Broken Hills Mine. Here a small flinty 
leader, known as Siever's, intersected certain of the reefs, and, although of Httle or no 
value itself, greatly increased the value of the veinstone which it intersected. 

In connection with these minor structural features it is probable that the com- 
mingUng of waters which have come from various sources, or have travelled in different 
directions and thus acquired different characters, has resulted in the precipitation of the 
sulphides and the associated electrum. 

(d.) Defth. 
The mining explorations of the past in this subdivision have demonstrated that 
depth below the existing surface has proved an important factor in connection with the 
distribution of the ores in the veins. 



61 

(2.) To the second group of deposits are referable all the other mineral deposits 
of the subdivision. 

Subgroup (a) comprises the veins of the old Waitekauri and Jubilee claims, and 
most of those at the Maoriland Claim (Waitekauri). the Rising Sun veins (Owharoa), 
the various veins of the Auckland and Glamorgan claims (Whangamata), and of the 
Luck-at-Last Claim (Wharekawa). Tliese present the vuggy, comby, massive, and 
occasionally crustified structures usually associated with fissure-fiHing of crystalline 
quartz. In addition to pyrite, one or more of the following sulphides may be present : 
Sphalerite, galena, chalcopyrite, or argentite. 

Subgroup (b) is more particularly confined to the rhyolites, and is well represented 
in the Tairua Broken Hills and other claims at Tairua, and in those of Wliarekirauponga. 
In the Tairua Broken Hills solid quartz, excepting as small parallel lenticular or 
ramifvTng stringers of thnty character, is almost absent, although the vein-material is 
in many cases confined to well-defined fissures. Sihcified bands or zones, fairly well 
defined, although showing no definite fissure-walls, are also conspicuous in these 
rhyolitic fields. Impure kaoHnitic clays and "silica" occur throughout the vein-material. 

The main ore-body of the Maoriland Claim, at Waitekauri. is associated with a 
fissure intersecting a bed of sihcified dacitic breccia, and may be included here. 

Subgroup (c) comprises many of the imptegnatioii deposits of the Gumtown field, 
of the Champion and Golden Belt at NeaTesville. and of the old Smilc-of-Fortune 
Claim at Owharoa. In these localities masses of the altered rocks have been more 
or less generally impregnated with siliceous ore-bearing solutions, and enclose ramifjnng 
veinlets and geodic nests of quartz, and scams stained with iron-oxides. These deposits 
in places, however, grade into somewhat definite mineraUzed bands, pipes, or veins. 

Sinter-deposits. 

SiUceous sinters, the deposits of hydrothennal springs, are of widespread occurrence 
throughout the subdi\'ision, and are usually confined to areas of rhyohtic or " Second 
Period " andesitic rocks. Many of the deposits arc cN-idently of the mushroom type, 
and of superficial deposition ; others appear to have some persistence in depth. A 
distinct stratification but little removed from the horizontal is often noticeable in the 
superficial deposits. 

The sinter consists mainly of amorphous or crA-ptocrj'stalline silica, generally white 
in colour, but varj'ing to grey, red, yellow, brown, or even black. Here and there are 
enclosed small geodic nests and thin lenticular veinlets of cr\'stalhne quartz. 

Pyrite and marcasite, with their oxidation-products, not infrequently occur dis- 
seminated throughout the mass. 

An analysis of a general sample of the sinters capping the hills on the Phoenix Claim, 
Ohui, reads : — 

Per Cent. 
Silica (SiOj) . . . . . . . . 97-50 



Ferric oxide (FejOj) 

Alumina (AljOj) 

Lime (CaO) 

Magnesia (MgO) 

Alkahes 

Sulphuric anhydride (SO 3) 

Moisture at 100° C. . . 

Combined water and organic matter 



0-80 
0-83 
Nil. 
Nil. 
Nil. 
Nil. 
012 
0-48 



99-73 
Aj8«ay — Gold, 7 gr. per ton ; silver, 8 gr. per ton. 



64 

At Komata, Waitekauri, Maratoto, and many other localities there is a marked 
deterioration or absence of pay-ore where the veins pass from the moderately hard 
propylite into soft shattered propyHte or chloritized dacites, or where a hea\y puggy 
selvage or crushed band separates the veinstone from the solid propyHte. 

In a bedded complex the flow rocks, probably owing to difierences in physical 
rather than in mineralogical character, constitute more productive vein-bearing coimtr}' 
than do the breccias. 

The pecuUar but not uncommon phenomenon designated by the miner as " ore to 
ore," or shoots " back to back," is well exhibited in the Tairua Hills Claim. Here 
north-south trending veins occur in massive rhyoUtc, and these carrj' their principal 
ore-shoots where they traverse an obliquely striking (north-east) belt. As, however, the 
rock within and immediately outside the hmits of this belt show? no appreciable change 
of character, these conditions must be due to some other factor than the influence of 
wall-rock or precipitation of the metals. It seems not unreasonable to suppose that 
there exists here a deep-seated cross-fissure, from which the impregnating ore-solutions 
have been dispersed throughout the various veins. 

The influence of certain of the wall-rocks as precipitants of sulphides will be apparent 
from subsequent description of the mines at Waihi and elsewhere. 

(c.) Minor Structural Features. 

Within an ore-shoot, high-grade ore is usually associated with the enlargements or 
Avider portions of the vein, and veinstone of considerably lower tenor \vith the contrac- 
tions or " pinches." This feature is especially apparent at Waihi, and also at Komata. 
Evidently the uninterrupted passage of the rainerahzing solution has been favourable to 
precipitation. The locaUties where numerous brandling veins are associated with the 
main ore-bodies — the zones of more pronoimced rock-fracture — have usually proved 
especially productive. Since, however, these loop veins, " droppers," and spur veins are 
generally confined to the more superficial horizons, the proximity to the surface may 
here have been an important factor in efEecting ore-deposition. 

Intersecting veins, faults, and cross-courses have in places influenced the locahzation 
of ores in the veins of the Waihi-Taima Subdi\nsion. Ores of comparatively low and 
fairly uniform grade, however, rarely show the same dependence on minor structural 
features as do richer bonanza ores, and these locaUzation-factors have had far more 
efiect in the Thames and Coromandel goldfields than in the area under re^^ew. 

At Waihi the occurrence of the most easterly shoot of ore on the Empire lode in 
the Grand Jimction Mine is genetically connected with the main fault which here 
intersects thie lode. The \\-idest cross-section of ore in the Royal lode is also found in 
close proximity to the same fault-line. 

The nearest parallel in this subdivision to the " flinties " or " indicator " veins so 
common at Thames is seen in the Tairua Broken Hills Mine. Here a small flinty 
leader, known as Siever's, intersected certain of the reefs, and, although of httle or no 
value itself, greatly increased the value of the veinstone which it intersected. 

In connection with these minor structural features it is probable that the com- 
mingUng of waters which have come from various sources, or have travelled in different 
directions and thus acquired different characters, has resulted in the precipitation of the 
sulphides and the associated electrum. 

(d.) Depth. 
The mining explorations of the past in this subdivision have demonstrated that 
depth below the existing surface has proved an important factor in connection with the 
distribution of the ores in the veins. 



51 

Chlorite, a complex iron-magnesium -aluminium silicate mostly derived from wall-rock 
alteration, is found in many quartz veins of the subdivision. 

Stilbite. — Stilbitc, one of the zeohte group, a hydrous sihcate of aluminium, calcium, 
and sodium, is seen occasionally in nests in the altered rhyolitcs, and also occurs in 
altered andcsite ("Second Period") at Waihi.* 

Laumontite. — Laumontite, a hydrous sihcate of aluminium and hme, another mineral 
of the zeohte group, was identified by P. G. Morgan* in altered rocks from Wailii. 

Valcncianite. — Valencianite, a sodium-potassium sihcate belonging to the monochnic 
feldspars, and alhed to adularia, was first identified by Lindgren as a secondary mineral 
in the altered rocks and veinstones of Waihi. It has since been isolated and analysed 
by Finlayson (see page 54). 

Fuller's Earth. — An impure fuller's earth has been found associated with the rhyohtic 
rocks at Waikino. The analysis of a sample forwarded by P. G. Morgan, with the analyst's 
remarks, is as follows : — 

Per Cent. 
" Sihca . . . . . . . . 40-45 



Alumina . 
Iron-oxide 
Lime 
Water 



34-32 
3-68 
1-09 

20-46 

100-00 



" The majority of fuller's earths contain less alumina and more sihca than arc shown 
in this analysis. Still, the sample may be suitable for some of the uses to which fuller's 
earth is put, for occasionally varieties of kaolinite are so used. It contains a consideral)lc 
portion of coaree particles, and is therefore not suital^lc for toilet-use in its present 
condition." 

Sericile. a hydrous aluminium-potassium sihcate, in a fine state of division, is 
found on the slickcnsidcd walls of certain vein fissures, and in veinstones formed by 
metasoinatic replacement. 

Kaolin, or Kaolinite. — Soft wliite clays (when dry, powdery aggregates) and grcjnsh- 
grccn waxy scales occur in portions of the veinstone of the Waihi Goldfield. An 
analysis of a sample washed free from grit, obtained from the Royal lode, No. 6 
level, Waihi Mine, gave the following result : — 

Per Cent 
Sihca (SiOj) .. 5fi-78 

Alumina (AI2O3) 
Ferric oxide (FcjO,) 
Ferrous oxide (FeO) 

0-10 

. . Nil. 

110 
O-II 
3-56 
0-59 
Nil. 
8-02 

100-00 



Manganous oxide (MnO) 
Lime (CaO) 
Magnesia (MgO) 
Soda (NajO) 
Potash (K,0) 
Titanium-o.xide (TiO^) 
Carbonic anhydride (COj) 
Loss on ignition 



2S-05 
1-69 



♦ Morgan, P. G., Trans. Aust. Inst. Min. Eng., 1902, vol. 8, p, 186. 



60 

Pymlusite and Wad. — The black oxides of manganese — pyrolusite and wad — are 
especially common in the oxidized vein-material of Komata, Waitekauri, Maratoto, and 
Waihi, in connection with the platy variety of quartz. These manganese-oxides often 
segregate, forming bands in veinstone, and also fill fissures in the wall-rock. 

Types of Mineral Deposits and Structure of the "N'eiv-material. 

The vein-material of the subdivision is the result both of the filHng of open fissures 
and of the replacement of wall-rocks. The form and extent of the veins, since they 
are mainly determined by the character of the fissuring, will be inferred from previous 
descriptions. 

It is not easy to separate the various mineral deposits into definite classes. From 
consideration of genesis, however, two types of deposits are recognizable, — 

(1.) Veins in which the primary vein-filling was mainly calcite or manganiferous 
calcite. The carbonate has in great part been replaced by quartz and 
sulphides, much of the quartz taking the form of the original carbonate. 
(2.) Veins and impregnations in which the quartz and associated minerals are 
the primary products of deposition from the minerahzing solutions, 
although in part modified by vadose waters and other agencies. On 
form, environment, and the relative extent to which fissure-filling and 
replacement have taken place, this class may, for sake of description, be 
subdi\aded as follows : — 

(a.) Fairly well-defined veins carrying normal crystalhne quartz and 
sulphides, and a minor amount of brecciated and replaced country. 

(b.) Veins or brecciated bands consisting mainly of country rock, 
silicified and otherwise minerahzed, with parallel and ramifj-ing stringers 
of quartz. In certain cases they also contain a considerable amount 
of kaolinitic material and hydrated sihca. 
(c.) Stock-work deposits. 
As may be expected, no hard lines separate these several types. 

(1.) To the first group belong the veins of Waihi, Golden Cross, Komata, and 
Maratoto, enclosed in andesites or dacites ; and probably those of Waihi Beach, 
enclosed in rhyohtes ; and of Ohui, enclosed in both andesites and rhyoUtes. The veins 
of this type vary from mere stringers to strong ore-bodies, in places exceeding 100 ft. 
in width. The walls are in places well defined, or, again, the boundaries of the 
original fissures are masked by replacement, the veinstone grading imperceptibly into 
wall-rock. The primary carbonate veiu-filhng is usually white, and coarsely crystalhne 
or massive. Considerable masses of it remain unreplaced below the more superficial 
horizons ; but within the range of vadose waters it has been mostly replaced or 
removed in solution with release of the manganese as the black oxides. The ore, 
which is of later origin than the great bulk of the carbonate, consists of quartz and 
various sulphides, and has been deposited in fissures opened in the calcite, or in fissures 
and brecciated bands in the wall-rock in immediate contact with the carbonate. From 
these fissures and brecciated bands widespread replacement of the carbonate, as well as 
of the wall-rock, has been effected. 

The character and structure of the veinstone is described in detail in connection 
with the various mines where this type of deposit occurs. ■^ 

In the cases of the claims at Waihi Beach and those at Ohui no examination of the 
veins below the ground-water level was possible. The abmidance of quartzose replace- 
ments after carbonate in the ore on the dumps, however, suggests that the veins 
belong to this type. 



67 

Chlorite, a complex iron-magnesium-alurninium silicate mostly derived from wall-rock 
alteration, is found in many quartz veins of the subdivision. 

Stilbitc. — Stilbite, one of the zeoUte group, a hydrous sihcate of aluminium, calcium, 
and sodium, is seen occasionally in nests in the altered rhyolites, and also occurs in 
altered andesite ( " Second Period") at Waihi.* 

Laumontite. — Laumontite, a hydrous sihcate of aluminium and hme, another mineral 
of the zeohte group, was identified by P. G. Morgan* in altered rocks from Waihi. 

Valencianite. — Valencianite, a sodium -potassium sihcate belonging to the monoclmic 
feldspars, and alhed to adularia, was first identified by Lindgren as a secondary mineral 
in the altered rocks and veinstones of Waihi. It has since been isolated and analvscd 
by Finlayson (see page 54). 

Fuller's Earth. — An impure fuller's earth has been found associated with the rhyohtic 
rocks at Waikino. The analysis of a sample forwarded by P. G. Morgan, with the analyst's 
remarks, is as follows : — 

Per Cent. 
" Sihca . . 4045 



Alumina 
Iron-oxide 
Lime 
Water 



34-32 
3-68 
109 

20-40 

100 00 



" Tiic majority of fuller's earths contain less alumina and more silua than are shown 
in this analysis. Still, the sample may be suitable for some of the uses to which fuller's 
earth is put, for occasionally varieties of kaolinite are so used. It contains a considerable 
portion of coarse particles, and is therefore not suitable for toilet-use in its present 
condition." 

Sericile, a hydrous aluminium-potassium sihcate, iu a line state of division, is 
found on the shckensided walls of certain vein fissures, and in veinstones formed by 
metasomatic replacement. 

Kaolin, or Kaolinite. — Soft wliite clays (when dry. powdery aggregates) and greyish- 
green waxy scales occur in portions of the veinstone of the Waihi Goldfield. An 
analysis of a sample washed free from grit, obtained from the Roval lode, No. 6 
level, Waihi Mine, gave the following result : — 

Per Cent 
Sihca (SiOj) . . . . . . .. 56-78 

Alumina (Al^Oj) 
Ferric oxide (FcjOa) 
Ferrous oxide (FeO) 



Manganous oxide (MnO) 
Lime (CaO) 
Magnesia (MgO) 
Soda (NajO) 
Potash (KjO) 
Titanium -oxide (TiO^) 
Carbonic anhydride (COj) 
Loss on ignition 



28-05 
1-69 



0-10 
Nil. 
1-10 
0-11 
3-56 
0-59 
Nil. 
8-02 

100-00 



• Morgan, P. G., Trans. Auat. Inst. Min. Eng., 1902, vol. 8, p. 186. 



60 

Pyrolusite and Wad. — The black oxides of manganese — pyrolusite and wad — are 
especially common in the oxidized vein-material of Komata, Waitekauri, Maratoto, and 
Waihi, in connection with the platy variety of quartz. These manganese-oxides often 
segregate, forming bands in veinstone, and also fill fissures in the wall-rock. 

Types of Mineral Deposits and Structure of the Veiv-material. 

The vein-material of the subdivision is the result both of the filling of open fissures 
and of the replacement of wall-rocks. The form and extent of the veins, since they 
are mainly determined by the character of the fissuring, will be inferred from previous 
descriptions. 

It is not easy to separate the various mineral deposits into definite classes. From 
consideration of genesis, however, two types of deposits are recognizable, — 

(1.) Veins in which the primary vein-filUng was mainly calcite or manganiferous 
calcite. The carbonate has in great part been replaced by quartz and 
sulphides, much of the quartz taking the form of the original carbonate. 
(2.) Veins and impregnations in wliich the quartz and associated minerals are 
the primary products of deposition from the minerahzing solutions, 
although in part modified by vadose waters and o'ther agencies. On 
form, environment, and the relative extent to which fissure-filhng and 
replacement have taken place, this class may, for sake of description, be 
subdivided as follows : — 

(a.) Fairly well-defined veins carrying normal crvstalhne quartz and 
sulphides, and a minor amount of brecciated and replaced country. 

(b.) Veins or brecciated bands consisting mainly of country rock, 
sihcified and otherwise minerahzed, with parallel and ramifying stringers 
of quartz. In certain cases they also contain a considerable amount 
of kaoUnitic material and hydrated sihca. 
(c.) Stock- work deposits. 
As may be expected, no hard lines separate these several types. 

(1.) To the first group belong the veins of Wailii, Golden Cross, Komata, and 
Maratoto, enclosed in andesites or dacites ; and probably those of Waihi Beach, 
enclosed in rhyoUtes ; and of Oliui, enclosed in both andesites and rhyohtes. The veins 
of this type vary from mere stringers to strong ore-bodies, in places exceeding 100 ft. 
in width. The walls are in places well defined, or, again, the boundaries of the 
original fissures are masked by replacement, the veinstone grading imperceptibly into 
wall-rock. The primary carbonate vein-filhng is usually white, and coarsely crystalHne 
or massive. Considerable masses of it remain unreplaced below the more superficial 
horizons ; but within the range of vadose waters it has been mostly replaced or 
removed in solution with release of the manganese as the black oxides. The ore, 
which is of later origin than the great bulk of the carbonate, consists of quartz and 
various sulphides, and has been deposited in fissures opened in the calcite, or in fissures 
and brecciated bands in the wall-rock in immediate contact with the carbonate. From 
these fissures and brecciated bands widespread replacement of the carbonate, as well as 
of the wall-rock, has been effected. 

The character and structure of the veinstone is described in detail in connection 
with the various mines where this type of deposit occurs. 

In the cases of the claims at Waihi Beach and those at Ohui no examination of the 
veins below the ground-water level was possible. The abundance of quartzosc replace- 
ments after carbonate in the ore on the dumps, however, suggests that the veins 
belong to this type. 



65 

Irrespective of the elevation of the vein-outcrops, little payable ore (excepting at 
Waihi) has been mined from depths exceeding 500 ft. below the existing surface. The 
downward litnit of the pay-ore mined appears, therefore, to have conformed roughly to 
surface-contours. 

Generally speaking, it is accepted as almost axiomatic that the ores of metalliferous 
veins decrease in depth. This feature is believed to be connected with the fundamental 
laws governing the retention in solution and the precipitation of the metals under 
varying conditions of temperature and pressure. Furthermore, a survey of the world's 
mining fields indicates that ore-de])osits genetically similar have, on the whole, a similar 
vertical range. In the Tertiar)- goldfields — into this category fall those of Hauraki— the 
ores have usually been deposited comparatively near the original surface, and the vertical 
range of profitable ore is restricted. In few of these fields has profitable mining been 
carried on below depths of l,5(M)ft. or l,8(X)ft. from the surface. 

Throughout the Waihi-Tairua field, excepting at Waihi. the amount of exploration 
that has been undertaken below depths of f/K) ft. to 600 ft. is small. Mining from 
shafts entails continuous expeiiditure for pu>nping, and where adit-work has been 
practicable the expense of the lengthy crosscutting to open deep ground is considerable. 
The chances, therefore, of the discover)- of ore-shoots in the zone extending from the 
surface to depths of from 200 ft. to 600 ft. have been very much greater than the 
chances of discovery at deeper horizons. Notwithstanding all this, it will generally 
be accepted as a fact that the upper zone indicated contains, or contained, more ore 
than the succeeding zone of, say, 600 ft. in thickness which underlies it. 

Apart from the effect in certain cases of a secondarj' enrichment of the upper 
portions of tlie veins which has attended the gradual degradation of the land-surface, 
the vertical distribution of ore is evidently dependent upon the conditions of original 
deposition and the extent to which denudation of the land-surface has subsequently 
progressed. As is. shown at Waihi, the land-surface at the period of vein-formation 
presented a ver}' irregular topography, and tliis ancient topography has evidently 
exercised a marked influence in determining the existing configuration. Denudation of 
the older volcanics, the prin(ij)al vein-bearing rocks, has in many j)Iaccs been retarded 
throughout longer or shorter periods of time by cappings of younger volcanics. 

In respect to the main ore-shoots located — namely, those of Golden Cross, Komata, 
and Wailii— the shoots of tln^ first-nanu-d locality have evidently suffered most from 
degradation of the land-surface, and those of Waihi least. As might be expected, the 
vertical range of the shoots worked in these localities has been found to be least at 
GJolden Cross and greatest at Waihi. 

At Waihi, Golden Cross, Komata, and Maratoto, dejjth below the surface that 
existed at the time of vein-formation was apparently the dominant factor determining 
the vertical range through which the original fissure-filling carbonates were replaced by 
quartzose veinstone and ore. Variations in depth imply variations in temperature 
and pressure, and the question of the ext«nt of this replacement refers principally to 
the relative solubilities of calcite and quartz under these varying conditions. The lack 
of knowledge as to the chemical character of the solvent solutions in the vein fissures, 
however, renders the problem complicated. 

Specific data regarding the solubility of silica are meagre, but it is considered that 
deposition from highly saturated solutions may be due to a loss either of heat or pressure. 
In the case of carbonates, and especially of calcium-carbonate, pressure is said to 
increase the solubihty in water saturated with COj, but only up to a certain degree, 
the miaximuiu amount that can be dissolved being 3,000 grams per ton.* On the other 

* Roscoe and Schorlemmer, " Treatise on Chemistry," vol. 2, p. 208. 
6 — Waihi-Tairua. 



66 

hand, increase of temperature decreases the solubility of calcitc, as the following figures \\-ill 
show* : From 7-5° C. to 9-5° C, 1,000 pts. HgO saturated with CO2 dissolves 1-181 pts. 
CaCOs ; from 26° C. to 28° C, 1,000 pts. HjO saturated with CO2 dissolves 0-855 pts. CaCO.,. 

On the whole, it would appear that hot sihceous ore-bearing solutions rising through 
the refractured calcitic veinstone would be more active in dissolving the calcite and 
depositing the quartzose ore at the cooler or more superficial than at the hotter or 
deeper horizons. This would imply an increase of calcite and a decrease of ore in 
depth, a conditio)! which has already been proven to obtain in most of these areas. 

The persistence of the ore-shoots in the rhyohtes has not yet been determined. 
In certain cases the veins enclosing these shoots do not reach the surface, a feature 
which imphes that the ores as originally deposited are intact. The shoots located, 
however, are of rather small dimensions, and cannot be inferred to have greater 
persistence than similar shoots in the andesitic rocks. 

Underground Temperatures. 

Observations were made during this survey with the object of determining at 
Waihi the " geothermal gradient " — the rate of increment of temperature with depth. 
There are, however, many factors affecting the temperature of the rocks in the mine- 
workings — the presence of heated water in the vein-channels, the seepage of cooler 
water from higher levels, the period during which the rocks have been exposed, 
the chemical action associated with oxidation, natural and artificial ventilating-currents, 
as well as the varying thennal conducti\'ity of the rocks. Although every effort was 
made to avoid the effects of interference-factors, and the observations were conducted 
upon approved methods, the results obtained were useless so far as estabhshing a 
gradient was concerned. 

The rock-temperatures obtained in the Waihi Mine from the 544 ft.. to the 1,150 ft. 
levels varied from 75° Fahr. to 85° Fahr., and in the Waihi Grand Junction from 
the 493 ft. to the 943 ft. levels, from 80° Fahr. to 88° Fahr. ; but in neither case did the 
temperatures show definite order wath increasing depth. In the Waihi Mine, at the 
1,150 ft. level, the water percolating through the rock from higher levels has a tempera- 
ture of 78° Fahr., while at the same horizon the water issuing from the Royal lode has 
a temperature of 89° Fahr. In the easterly workings of the Waihi Grand Junction, 
at the 944 ft. level, the temperature of the water issiiing from the vein fissures when 
first intersected had a temperature of 91° Fahr., whereas the rock in crosscuts gave 
readings about 4° lower. 

Apparently the temperature throughout the field at any particular horizon is by 
no means constant. It is stated by the Waihi Company's officials that in developing 
the mine from No. 2 shaft^ — i.e., from No. 2 (206 ft.) level down to No. 6 (544 ft.) 
level — it was always found that the water from the Welcome lode west of No. 2 shaft 
was " warm to the feel of the hand," while the water east of No. 2 shaft " was 
considerably cooler." No temperatures were recorded. 

In the Waihi Grand Junction Mine the temperatures encountered in the more easterlv 
workings were higher than those which obtained farther westward ; and in the Waihi 
Extended, still farther eastward of the Jmiction, even higher temperatures are reported. 
An air-temperature of 101° Fahr. was observed by the writers in the Waihi Extended 
south-east crosscut at No. 5 (960 ft.) level after work had been suspended. 

The various facts cited lead to the conclusion that part of the ground-water in the 
vein-channels is ascending from deeper horizons, and that the upward how is far 
from uniform throughout the extent of the fissure-veins, but partakes somewhat of 
the nature of localized thermal springs. With an average rock-temperature of, say, 



* Corsa Z. Anal., 8, 145. 



67 

85° Fahr. at the 1,000 ft. level, and a mean temperature of, say, 56° Fahr. at the 
50 ft. horizon, and assuming the intermediate levels had shown a gradual increment 
with depth, a " geothennal gradient " of approximately 1° Fahr. in 32-8 ft. would 
have been indicated. For reasons already stated, however, no such estimate can be 
accepted.* 

Underground Gases. 

In none of the mines of the Wailii-Tairua Subdi\nsion does mine-gas occur to 
anything like the same extent as at Thames. At the latter localitv the gas had a 
specific gra%nty of 1-19 per cent, (air = 1). and a composition of 01-2 per cent, lutrogen 
and 38-8 per cent, carbon-dioxide. 

At Waihi in certain parts of both the Waihi and Orand Junction n\ines a light 
gas issues during periods of low barometric pressure, and accumulates in the roof of the 
workings. This gas, when not too diffused, extinguishes the candle-flame. The gas 
occurs more abundantly than elsewhere in the Trout crosscut at No. 8 (850 ft.) level, 
Waihi Mine, and on the Mary lode, No. 5 (943 ft.) level, Waihi Grand Junction Mine. 
In the fonner locality relatively permeable countr>' rock in various stages of oxidation, 
with numerous small veins and fissures, is penetrated in the crosscut and in a bore- 
hole projected from its terminal face. In the Mary lode very cavernous vuggy veinstone, 
carrying much secondari- iron-pyrite, occurs. It is probable that this gas is due to air 
which at normal barometric pressures permeates the country rock or the veinstone, 
and gives up oxygen to the ferrous compounds in the ferro-magnesian minerals, or 
for the oxidation of sulphides. When the barometer falls below 29-6 in. this reduced 
air issues from the rocks. In the case of the Trout borehole, it has been fre(|uently 
observed that air flows into the hole when the baromet<'r i.s liigh. and gas (reduced air) 
flows out when the barometer is low. 

A sample (collected by one of the company's oflTicials during a period of low 
atmospheric pressure) of the air from the Mary lode, Waihi (irand .lunction Mine, was 
submitted for analysis, with the following result f : — 

Per Cent. 
Carbon-dioxide . . . . . . . . Nil. 

Oxygen .. .. .. .. .. .. 17-20 

Nitrogen .. .. .. .. 82-80 



100-00 
Underorodnd Water. 

The ground-water level throughout the subdi\nsion, where not affected by pumping, 
is directly related to the topography, following, as is usual, somewhat more modified 
contours than those of the land-surface. 

The andesites, dacites, and rhyohtes carr\' little more than the water of imbibition, 
except where the rock is much jointed or traversed by open fissures and mineral veins, 
or where unconfonnities, accompanied by conglomerate, exist. Again, where solid rocks do 
not reach the surface the loose weathered overburden offers free passage to circulating waters. 

All mining operations below the ground-water level in the andesites and dacites 
revealed the existence of considerable quantities of water immediately the quartz veins 
or other circulation-channels were intersected. Mining in the rhyolites below the water 
level has been conducted^ in only three localities — namely, Tairua Broken Hills, Phoenix 

* At Thames, where more-satisfactory results were obtained, the approximate gra<lient determined 
by one of the writers (C. Fraser) was 1° Fahr. in 43 5 ft. 

t As traces of alkali were detected in the bottle used for collection, the sample was an unsatisfactory one, 
and this may account for no carbon-ilioxide being present when analysed. 

+ In the Waihi Beach Mine practically no water was encountered in drifting upon the veins (although the 
workings were below sea-level) until a large open cross-course admitting sea- water was intersected. 

5 * — Waihi-Tairua. 



68 



(Ohui), and Waihi Beacli — and in each case it would appear tliat the volume of water 
encountered was less than is usual in similarly situated workings in andesites. 

At Waihi itself the rhyolitic plain, from which rises the andesitic hills, has a 
general elevation of 370 ft., the surface drainage-channels being the Oliinemuri Eiver 
and its tributaries. The original ground-water level conformed to the configuration of 
the country, and below the plain it stands (excepting where mine-pumping has lowered 
it) slightly above the level of the river. This is proved by the fact that the water 
in two abandoned shafts in the Pride-of- Waihi Claim stands within 20 ft. of the collars. 
In the Waihi Reefs ConsoUdated shaft, too, before pumping was resumed the water rose 
to within 16 ft. of the surface. No records of " first-water " have been preserved by 
the Waihi Gold-mining Company, but it doubtless at each shaft showed dependence upon 
surface-configuration. 

The following table, covering the years 1902-10, shows the amount of water pumped 
by the diiierent companies in Waihi, and also the rainfall recorded at the local meteoro- 
logical station : — 









Water pumped. 








Rainfall, 

in 
Inches. 










Year. 


Waihi Gold- 
Mining Company. 


Waihi 
Grand Junction 


Waihi 
Extended 


Remarks. 






Company. 


Company. 








Gallons. 


Gallons. 


Gallons. 




1902 


78-55 


439,196,800 


16,146,080 


Not recorded. 




1903 


82-88 


359,083,925 


10,670,880 


)) 




1904 


83-05 


536,629,840 


17,267,680 


)> 


From July, 1904, Waihi 
Company's No. 7 (700 ft.) 
level and Grand Junction 
No. 3 level were being 
drained. 


1905 


65-51 


494,242,560 


5,805,396 


,, 




1906 


65-14 


679,707,996 


11,696,104 


J) 


From March, 1906, Waihi 
Company's No. 8 (850 ft.) 
level and Grand Junction 
No. 4 level were being 
drained. 


1907 


119-35 


507,428,360 


5,065,789 


5J 




1908 


88-32 


516,237,650 


42,185,126 


); 




1909 


104-45 


738,934,160 


20,589,860 


J> 


From 10th December, 1908, 
Waihi Company's No. 9 
(1,000 ft.) level and Grand 
Junction No. 5 (944 ft.) 
level were being drained. 


1910 


101-07 


556,731,024 


1,526,758 


(App roxi- 
m a t e 1 y 
15,000 gals, 
per day) = 


Waihi Extended Company 
sinking below general 
drainage-level. 










5,475,000 





The Waihi Reefs ConsoUdated Company, in its shaft-sinking operations, is pumping 
at present (end of 1910) about 96,000 gallons per day. 

From the above statistics it will be observed that the quantity of water pumped 
does not vary, at least immediately, with the rainfall. In 1907, with a record rainfall, 
the amoimt of water hfted was less than in 1908. It is also apparent that the large 
lodes with their veinstones of cellular and cavernous character, which form the trunk 
circulation-channels, act as storage -reservoirs for enormous quantities of water. In sink- 



69 

iiig shafts through country rock not intersected by fissures, Uttle water is encountered. 
After, however, " cutting the water " at a new level a great inrush takes place, and it 
usually takes about eight months before the flow for the new level becomes normal. 
This normal flow has been found at the Waihi Company's pumpiiig-station to increase 
approximately in the ratio of 0-9 gallons per foot of sinking. Thus, at the 1,000 ft. 
level it is about 900 gallons per minute. 

The artificially maintained water-level, ovsing toffthc permeabihty of the lodes, rises 
only very gradually as one departs from the Waihi Company's pumping-station. 'Jhe 
Waihi Grand Junction levels are opened about 25 ft. above, and tlie Waihi Extended 
levels about 30 ft. above, the approximately corresponding levels of the Waihi Mine. It 
is recorded that, although pumping at the main station was suspended for twenty- 
seven days early in 1909, the effect was not evident in the Waihi Extended workings, 
50 chains away. 

At the Waihi Reefs Consolidated Claim, where the shaft penetrated the rhyoUtic 
formation for about 400 ft., and is now being sunk through the younger andcsite, the 
greater part of the water comes from a conglomerate bed between the rhyolite and the 
andesit©. 

Representative samples of the mine-waters for analysis were taken from the deepest 
horizons on the field — (a.) No. 10 (1,150 ft.) level, Waihi Mine, from a reef exposed in 
the comer of the shaft-chamber of No. 5 shaft ; (6) from a small fissure in the main 
north-east crosscut, 300 ft. froju No. 5 shaft ; (c) from the bottom of the Waihi 
Extended shaft, 1,040 ft. from collar. 

Silica (.SiOa).. 
Akunina (AljOy) 
Ferrous oxide (FeO) . . 
Lime (CaO) . . 
Magnesia (MgO) 
Potash (KoO) 
Soda (Na^b) 
' Chlorine (CI) 
Sulphuric anhydride (SO3) 
Carbonic anhydride (CO2) 
Water combined as bicarbonate (ILO).. 



(a.) 
2-Ou 


Parts per 100,000. 
(6.) 
3-On 


(c.) 
2-60 


O-lD 


0-70 


0-20 


0-15 


0-20 


0-07 


6-20 


8-25 


4-00 


0-50 


0-70 


0-70 


2 00 


2-10 


2-10 


3-10 


4-00 


3-60 


1-80 


2-20 


1-80 


6-30 


8-40 


1-20 


8-20 


10-70 


10-90 


1-60 


2-10 


2-20 


32-25 


42-35 


29-37 


0-40 


0-50 


0-40 



Less oxygen, ecjuivalent to CI. 

Total sohds . . . . . . 31-85 41-85 28-97 

These results may be restated as follows : — 

Potassium-chloride (KCl) 
Sodium-chloride (NaCl) 
Sodium-sulphate (NagSO^) 
Calcium-sulphate (CaS04) 
Magnesium-sulphate (MgS04) 
Aluminium-sulphate {Al2(S04)3) 
Sodium-bicarbonate (NaHCOj) 
Calcium-bicarbonate (CaHjlCOa),) 
Ferrous bicarbonate (FeHjlCOgJa) 
Sodium-siUcate (Na20.4Si02) 

Total sohds . . . . 31-85 41-85 28-97 



(«•) 

3-10 


(6.) 
3-40 


(c.) 
3-80 


0-60 


1-00 


Nil. 


5-50 


6-50 


Nil. 


2-70 


3-85 


Nil. 


1-50 


2-10 


1-20 


1-00 


1-70 


0-50 


Nil 


Nil 


8-40 


4-70 


19-20 


11-67 


0-35 


0-50 


0-25 


2-40 


3-60 


3-15 



70 

The solids iu all these waters, it will be observed, are evidently, in the main, the 
results of the leaching of the ordinary rock-forming constituents of the propyUtes. The 
Waihi waters differ from those of the 1,000 ft. level of Thames (see Bulletin No. 10, 
page 49) mainly in that they contain very much less chlorides (Thames water — chlorine, 
61-10 gr. per gallon). They moreover, as might have been expected owing to the 
presence of secondary ortlioclase iu the propylites, contain potash, the existence of 
which was not reported in the Thames waters. 



71 



CHAPTER VI. 



DETAILED DESCRIPTIONS OF MINING AREAS AND MINING CLAIMS. 





Page 




The Vicinity of Gumtown 


.. 72 




Kajwwai Claim 


.. 72 




Welcome Jack Claim 


.. 74 




Big Beetle Claim . . 


.. 74 




Golden Reefs Claim 


.. 75 




Boat Harbour and Vicinity 


.. 75 




Boat Harbour 


.. 75 




Neave'p; Bav 


.. 75 




Te Karo .'. 


.. 75 




Stony ( 'reek 


76 




Lower Tairua 


7U 




Tairua Broken liills Claim . . 


1 1 




'J'airua Golden Hills Claim . . 


. . 81 




Tairua Monarch Consolidated Claijn 


. . 82 




Other Claims 


. . 83 




Neave.sville Area 


. . 83 




Golden Belt Claim . . 


. . 84 




Champion Claim 


. . 86 




Beady Bullion Claims 


. . 87 




Chelmsford Claim . . 


. . 87 




" Fourth Branch " of Tairua Hiver 


. . 88 




Tairua Valley above " Fourth Branch 


. . 88 




Ohui 


.. 88 




PhcenLx Claim 


. 89 




Dreadnought Claim 


. 91 




Great Mexican Claim 


. 91 




Wharekawa \'all<y . . 


. 92 




Luck-at-La.st Claim 


. 92 




Goldwin Claim 


. 93 




Whangamata 


. 95 




Auckland Claim 


. 95 




Glamorgan Claim . . 


. 96 




Wharekirauponga 


. 97 




Piu-iri X'alley 


. 98 




Omahu Valley 


. 98 




Sheet Anclior Claim 


. 99 




We Three Claim 


. 99 




Klondike Claim 


. 100 




Maratoto Valley 


. 100 




Walker's Maratoto . . 


. 100 




Maratoto ConsoUdated 


. 101 




Silverstream Claim 


. 102 




Tclluride-s Proprietary Claims 


. 103 




Peel's ( 'reek Prospects 


. 104 




Waitekauri Extended Claim.. 


. 104 




Komata ]>Lstrict 


. 105 




Komata Reefs Mine 


. 105 




Waitekauri Valley 


. 108 




Golden Cros-s Claim 


. 108 




Grace Darling Claim 


. Ill 




Durbar Claim 


. 112 




Huanui Claim 


. 113 




Old Waitekauri Claim 


. 113 




Scotia Claim 


. 114 




Jubilee Claim 


. 115 




Maoriland Claim 


. 116 




Owharoa 


. 117 1 




Rising Sun 


. 118 { 




Mackaytown 


.119 1 




Ascot Ciimabar Mine 


. 119 




Waihi Beach 


. 121 




Waihi Beach Claims 


. 122 




Waihi Goldfield 


. 123 ' 




Introduction 


. 123 


Topography 


. 123 





Waihi Goldfield — continued. 
Geology . . 

(a.) Dacites ("First Perioa " Vol- 

canics) 
(6.) Andesites ("Second Period" 

Volcanics) 
(c.) Rhyolites(" Third Per.od " Vol- 
canics) 



Page 
123 
124 
125 



125 



((/. I .\ndesitic Rocks of Doubtful Age 125 

Detailed Structure . . . . 126 

Vein-system .. .. ..128 

Origin of the Vein Fissures . . . . 1 29 

Sequence of Mineral Deposition in the 

Veins . . . . . . ..132 

Nature of the Vein-material . . . . 1;J4 

The Ore-shoots .. .. ..140 

Waihi iMine . . .143 

£(|uipment . . 143 

Martha Section .. ..145 

Development . . . . 145 

Geological Structure . . . . 145 

Veins and Ore-deposits . . .145 

.Martha Loile .147 

Branches of Martha . . . . 1 50 

Empire Lode 1.5() 

Royal Lode . . . . 151 

Edward Lode . . 152 

Union-Silverton Section ..158 

Union lx>de . . . . .159 

Amaranth Lode . . KJO 

Silverton Ijode . . 160 

Mascotte Lode. . . . 100 

Statistics, Ex])loratory Work pri- 

cecding and proposed, &c. . . 160 

Ore-reserve .. .. .. UiO 

Output . . .101 

Ex))loration . . 101 

Waihi Grand Junction Mijiu. . .. 161 

E(|uipment . . . . . . 162 

(Jrand . I unction Eastern Section . . 162 

L'nderground Development . . 162 

Geological Structure . . . . 1 6:5 

Veins .. .. 164 

Martha Lode . . 164 

No. 2 Lode . . . . 164 

.Mary Lode . . . . . . 165 

Grace L<jde . . . . . . 165 

Emj)ire Lode .. ..165 

Royal Lode . . . . 166 

George Lode . . 167 

Other Veins. . . . 167 

Western Section . . . . 168 

Statistics, Exploraliciii proceeding 

and proposed, &c. . . . . 168 

Ore-reserve . . . . . . 168 

Output . . 168 

Exploration . . 168 

Waihi Extended Claim . . 169 

Geological Structure . . 169 

Veins . . . . . . 1 70 

Pride of Waihi Claim . . 171 

Waihi Reefs Consolidated Claim . . 171 

Other Claims .. .. 171 

Waihi Romulus Claims ..171 

Waihi Gladstone Claim ,. ,.172 



72 

Thk Vicinity of Gumtown. 

MiNiNc in tlic Guintowii district has been fonfined to ;ui urcu of about one and a 
half s(iuai'e miles of tlie higli country lyiug between the Kapowai and Rangihau Ijranches 
of the main Waiwawa River, which flows into Mercury Bay. The mining camp is 
coiniccted with the Gumtown Settlement by a graded road running through the Rangihau 
Valley, and, again, by a more direct but unformed track five miles and a half long, 
which follows the ridges westward of Oteao Stream. 

Several claims have been worked by companies or private individuyls, but at the 
present time the Kapowai Company alone is operating in this district. The value of 
the total gold-silver output of the camp up to the end of I'JlO was £14,062. 

The rocks of the mining countrj- are pumiceous rhyolitic tuflis and biotite-rhyohtes, 
all considerably altered, and, especially in certain bands, more or less silicified. Within 
this rhyolitic complex there appears in the road-cuttings, about 15 chains south-west of 
the old Welcome Jack battery, a small isolated outcro]) of black glassy pyroxene- 
andesite, apparently an intrusive alhed to the Table Mountain dykes. 

All of the ore mined in the Gumtown district, except that from the Welcome .Tack 
reef, has been derived from minerahzed bands or zones in pumiceous rhyohtic tufls. 
These mineralized bands are more silicified than the general mass of the country ; sohd 
vein-quartz due to filhng of open fissures is absent or inconspicuous. Shearing and 
brecciation \nthin these minerahzed bands give rise to a rubbly structure and a good 
deal of clayey material. The rust-stained appearance of the minerahzed formations 
results from oxidation of pyrite, although few remnants of the original sulphides now 
survive. The larger minerahzed zones or bands are sparsely auriferous throughout, and 
the pay-ore is confined to lenticular shoots, the positions of which appear to be deter- 
mined by secondary fracturing or fissuring. The strike of a shoot is sometimes ahgned 
with that of the minerahzed band in which it occurs, or, again, may cross it even 
transversely. The rust-stained waUs of some of the reticulated fissures intersecting 
silicified tufi have been found thickly " peppered " with finely divided gold, quite 
miaccompanied by quartz. 

The configuration of the country has permitted of all underground mining being 
carried out from adits ; and witliin the ore-bearing formation the erratic disposition of 
the pay-shoot has been responsible for numerous intersecting drifts and crosscuts, 
resembhng the pillar-and-stall method of mining. At the outcrops, ore has in places 
been mined by open-cutting. 

The only claim now in existence is the Kapowai. Abandoned claims are the 
Welcome Jack, Big Beetle, and Golden Reefs. 

The Kapowai Claim (area, 79 acres 4 perches * ; ownei"s, the Kapowai Gold-mining 
Company, Limited, Auckland). — The Kapowai Claim is situated in the high country of the 
•Kapowai-Rangihau ridge, just to the south of the " Big Slip." It has been worked 
almost continuously since the opening of the Gumtown field, first by the Kapowai Gold- 
mining Company (old), 1899-1903 ; then by Michael O'Connor, 1903-6 ; and since 1906 
by the present company. 

The mining operations carried on by Mr. O'Connor have alone shown a profit, as 
this proprietor reaped the benefit of certain micompleted developmental work done by 
the pre\aous owners. The total output of the mine is 3,408 oz. of gold-silver bulHon, 
valued at £8,162, and derived from 4,182 tons of ore. 

Equipment consists of an eight-stamp mill, four berdans, and a small C3'anide 
plant. Steam-power is employed. Access to the principal workings is given by two 
adits, which are vertically 133 ft. apart. Above these several smaller adits exist. 



* Total area held by the Kapowai Company, mcluding the Perseverance and Golden Reefs claims. 



78 

The country rock is an altered rliyolitic tuil (pumiccous), showing Uttle or no 
structural bedding, and the ore-shoots are confined to a wide east-west trending silicified 
band. The foot-wall of this band or zone is fairly well defined, and dips southward 
at angles approaching 45°, but the hanging-wall portion appears to merge gradually into 
ordinary altered tuff. This is represented in the following sketch-plan and section, which 
also shows the disposition of the shoots of pay-ore : — 



A 



4 




A 




A 


•1 


V 


A 


■u 


* 


^ 












A ' 












< 




< 








• 


' . 


V 


<3 


\- 


A 


c 


/> 


■ 


>^ 


" A 


, A 


^^m 


« 
^ 


««■ 




< 


• 'v 


{• • 


. 1 


^ 






"] 




^ 






4 


a. 




A 


■ !/> 






• 


. r 


A 






a 


• 


/*. 




< 


i> 


* 


.1- 




r 



SiZtcifhedL harid of 



A rhyolttx 


x: 1 


'^^C ri. 


. 1 


. A, ■ aI .1 * 


■|* ■ 


* 






A 


^( ■ c 






<4 . 1 /^ 


id 


'if,* 


" ' 


V 


. ^1. 


J 


L^'' 


• ^'-i-i 


A 


.^>- 


1 


I- 


■ 


r 


^1 


~^ 


1 ■ ' A 


. a , 


?■ • 


V 


^:^; f- 


^t 


.u 


• V 

M • 


> 


. L . b\ <1 . ' 1 


'•-,''„ 




A 


«3 


A 

/I 










PLAN 



SECTION 



DiAOKAMMATIC SKETCH .SHIIWISO THE DISPOSITION OF THE OrE-SHOOTS IN THE KaI'OWAI MiNE. 

(c.) Cro.ss rcff. (d.) O'Connor's ore-shoot, (c.) Small orc-])i|)e. 



A " cross-reef," which 
2 level to a height of 



The ore occurs in the form of segregated vein-formations and lenticular pipes within 
the mineralized breccia-bands, and differs little from the general mass of the minerahzed 
breccia, excepting in respect to gold-silver content. O'Connor's pipe-like ore-shoot 
raeiisured 5() ft. in its longest diameter, and Imd a maximum stope-width of 30 ft. It 
was followed upward for 70 ft., and was found to split into branch(!3 on approaching 
the surface. A minor ore-pipe, which was 12 ft. in longest diameter, and dipped 
eiisterly at high angles, was stoped upward for 50 ft. or 60 ft. 
had a width of about 2 ft. to 3 ft., was stoped from the No. 
about 150 ft. 

The main low-level crosscut at the time of examination had just intersected the 
minerahzed breccia-band, but had not reached the point where the downward continua- 
tion of certain of the ore-shoots were expected. As all the known ore-occurrences 
appear to be closely connected with secondary enrichment or superficial concentrations, 
the values may be expected to diminish in depth. 

The claim is by no means an easy one to prospect ; the lensoid pipes of ore are 
small and erratic, and there is nothing to indicate where they may be expected to occur. 
Little or no attention appears to have been given to ascertaining the value of the gold- 
silver contents in the general mass of the siUcified band enclosing the various ore-pipes. 



74 

In view of the water-power available at the falls in the Rangihau Stream not far from 
the mine, the question as to the potentiahties of the claim to afiord a large tonnage of 
low-grade ore should be worth investigating. 

The Welcome Jack (old). — The Welcome Jack Claim, now abandoned, was situated 
immediately to the southward of the Kapowai, the principal workings being about 
25 chains north of Welcome Jack trig. The claim was worked from 1899 to 1903 by 
the Welcome Jack Gold-mining Company, Auckland, and the following output is 
recorded: Tons crushed, 466; buUiou produced, 1,628 oz.; value, £3,013. 

The company's battery consisted of five light stamps and two berdans, and was 
connected with the main adit by aerial tram. Mining was carried on from two levels, 
spaced at about 60 ft. and 160 ft. below the outcrop of the reef. Both of these adits 
are now inaccessible. The country rock enclosing the reef is an altered biotite-rhyohte, 
but pumiceous tufi occurs in the near \acinity. The reef, which strikes N. 88° W., and 
dips southward at high angles, had, where stoped, an average width of from 6 in. to 
9 in. , and consisted of white granular and cellular quartz with patches of brecciated and 
siUcified rhyoUte. The pay-shoot measured about 200 ft. in length in the upper level, 
and was fomid to wedge out when followed dowiiward, the lower hmit of the pay-ore 
being about 100 ft. below the outcrop. Free gold was intimately associated with the 
soUd white cjuartz, and occasionally ^^'ith small bands of sulphides- — mainly pyrite. 
Some of the richest ore, however, occurred in and near a narrow pipeclay seam. That 
the outcrop of the pay-shoot contained high values is e\'idenced by the two lots of 
trial crushings sent to Thames and to Auckland respectively. The former, a parcel of 
5 tons, returned £550 ; the latter, 6 tons, £240. It is probable that the extraction at 
the small battery erected on the claim did not greatly exceed 50 per cent, of the assay 
value. The reef at the low-level adit, it is stated, maintained its size, and was well 
defined, but carried Uttle or uo gold. 

A large in-egular parallel vein-fonnation can be seen outcropping about 6 chains 
south of the Welcome Jack reef, and, judging by surface shoadings, strikes across 
Bull's Rmi towards the Rangihau Stream. It consists of siUcified rhyoUte or rhyoUtic 
tuff, with veinlets and bunches of white quartz, but \\-ith little or no visible pyrite or 
other sulphides. At no point along its outcrop has it afforded encouraging prospects. 

The Big Beetle Claim [old). — This claim, which is now abandoned, was situated 
immediately to the south-west of the Welcome Jack. It was worked from 1899 to 1904 
by the Big Beetle Gold-mining Company, and from 1904 to 1905 by tributers and 
private iudi\-iduals. The battery returns are as follows : Tons crushed, 543 ; bullion 
produced, 956 oz. ; value, £2,688. Most of the material crushed was mined from a flat- 
Ijang reef-formation consisting of siUcified rhyoUtic tuff, and containing gold mostly 
" peppered " on the rust-stained walls of fissures and selvages. The ore which this 
formation afforded was frequently very " showy," but when crushed seldom or never 
gave the results expected. The average value of the material crushed, however, is 
fairly high, but much hand-picking was practised, owing to the fact that the company's 
mill consisted of only three stamps. As in the Kapowai, no attempt appears to have 
been made here to determine whether or not this or any of the other similar deposits 
is capable of affording low-grade ore in sufficient quantity to be of commercial 
importance. 

The Golden Reefs Claim. — This claim is part of the present Kapowai. When worked 
as a separate claim in 1901 a lode-formation from 1 ft. to 3 ft. wide was discovered. 
Thirty-one tons of ore was cnished, for 30 oz. 15 dwt. of bulUon, valued at £77 9s. Id. 



75 

Boat Harbour axd Vicinity. 

Fur many years the fact that a belt of coastal country, exteiidiiif!; from Boat 
Harbour southward about two miles to Te Karo Beach, is auriferous has been recognized. 
Te Karo Beach is, as the crow flies, three miles north of the entrance to Tairua 
Harbour. Prospecting-work has been carried on only intermittently, and the amount of 
exploration done is small. The only recorded bullion return is that of 8 oz. 12 dwt., 
obtained in the year 1891 by Hornibrooke and party. 

The country rock throughout the whole of the area consists of andesitic and 
dacitic flows and breccias, fairly fresh, and in various stages of alteration. These 
volcanics are probably referable to the " Second Period." but the minerahzation is more 
hkely to have resulted from the eruptive " after-actions " associated witli the extrusions 
of the " Third Period " rhyohtcs, which to the westward flank and overhe the andesitic 
rocks. 

Quartz veins occur in the creek draining into Boat Harbour, also on the north head- 
land of Neavc's Bay and on the headland south of Te Karo Beach. SiUceous sinters arc 
conspicuous in the country lying between 'I'e Karo and the valley of Graham's Creek, 
flowing into Tairua Harbour. 

Boat Harbour. — The particular locality which has received most attention is in the 
valley of the largest stream draining into Boat Harbour, and about 50 chains from the 
coast-hne. Here a large quartz reef is exposed near the main fork of the creek, and 
is traceable on the surface for 10 or 15 chains. This reef, which strikes N. 25° E. and 
dips to the south-eastward at angles approximating 45". measures from -1ft. to 10 ft. in 
width. The veinstone consists of o.vidized, compact, and rul)bly (juartz, considerably 
stained with iron-oxides, and also includes much replaced wall-rock. The walls are in 
places well marked, and, again, are rather indefinite. Two small adits at different 
levels give access to drifts which follow the reef for short distances. The "dump" ore 
gives on panning a few "colours" of gold; and a sample yielded on assay 3 dwt. 3 gr. 
of gold and 2 dwt. 4 gr. of silver per ton. The bullion, amounting to 8 oz. 12 dwt., 
obtained by Hornibrodkc and paity from 14 tons of ore is probably attributable to 
this reef. 

Small veins are reported to exist not far from the big reef, and one of these is 
said to have yielded small pockets of specimen-stone. The position of these old 
workings could not be located, owing to the dense vegetation wliich covers the country. 

Neaves Bay. — At Ncave's Bay a large quartz reef outcrops between high and low 
watermarks, striking about north-south and ranging from 15ft. to 20ft. in width. The 
veinstone consists of hard white quartz, both compact and vesicular, stained with iron- 
oxides and containing remnants of pyrite. A general sample taken from across the 
outcrop yielded 1 dwt. 13 gr. of gold and 1 dwt. 21 gr. of silver per ton. A few small 
collapsed drives are to be seen in the locahty. and an attempt has been made to sink a 
shaft. 

Te Karo. — On the coastal headland 20 chains north of the mouth of Te Karo Stream 
a large reef-formation striking north-east is seen in the chff-face, and again on a small 
islet 10 chains from the coast. This reef-formation measures altogether about 60 ft. in 
width, and consists of sheets of quartz separated by sheets of altered and partly silicified 
andesite, the whole mass containing iron-oxides, and here and there remnants of pyrite. 
A rough general sample taken across the full width gave a gold and silver content of 
only 1 gr. and 14 gr., respectively. 

The siUceous sinter-deposits have considerable development south of Te Karo, but 
samples taken gave on assay no trace of gold or silver. 



76 

Mention sliould be made here of certain biaek-saiid deposits oeeuning on Te Karo 
Beach and on the beach immediately to the north of Tc Karo headland. The opinion 
has at times been expressed that these sands would pay to work if a suitable treatment- 
process could be devised, and some attempt has been made to carry on sluicing at the 
mouth of one of the small creeks. The sands certainly give gold on panning, but the 
bulk assay value does not exceed 2s. 6d. per ton, and, as the quantity available is 
small, any attempt to treat them commercially must result in failure. 

In regard to the Boat Harbour - Te Karo area as a whole, the prospects of opening 
up a payable auriferous deposit of any considerable extent are not promising. The belts 
of rock showing favourable alteration are few and local ; the large reefs are low grade ; 
and the small leaders are erratic, and have been proved to carry but few pockets of 
rich ore. 

Stony Creek. 

Stony Creek, flo%ving into the Whitianga Estuary, drains a considerable area of 
rhyohtic country, and has long been known to carry detrital gold in its debris. 

The prospector has traced the source of this gold to the base of the high scarp 
which forms the northern side of the water-parting separating Stony Creek from Pipi 
Creek, a tributary of the Tairua River. Here old trenches are visible, and a prospecting- 
adit has been driven 300 ft. 

The rock enclosing the old workings is a greenish-grey altered and pyritized horn- 
blende dacite, which in places much resembles a rhyohte, and is in fact referable to the 
period of the Phocene rhyohtic extrusions. The gold of the creek-gravels appears to 
have been derived from rusty clay-filled joint planes and irregular veinlets of comby or 
sugary quartz traversing this rock. In the prospecting-drive several of these, varying 
in width from ^ in. to 2 in., have been intersected. 

Sihceous sinters are widespread in the high country drained by the headwaters of 
Stony Creek, and the pumiceous tuffs and the rhyohtes and dacites have in places been 
impregnated mth sihca. These sinters and sihcified rocks contain gold, but in almost 
neghgible quantities. 

The prospects of Stony Creek ever affording a payable metalhferous deposit are 
remote. 

Lower Tairua. 

The mining area of Lower Tairua stretches along both sides of the Tairua River, 
from the mouth of Ti-tree Creek to the jimction of the " Second Branch." About the 
centre of the locahty a township with a population of about two hundred is scattered 
along both banks of the river. 

The first discoveries at Tairua were made about 1893, on ground which is now the 
property of the Golden Hills Company ; but it was not until 1896, following the dis- 
covery of gold on the Broken Hills Claim, that a rush set in, and much prospecting 
was done. The total output of the field up to the end of 1910 is valued at £89,649. 

The auriferous rocks of the locahty consist of " Third Period " rhyohtic lavas and 
breccias. Andesitic rocks, however, appear on the western side of the Golden Hills 
Claim. The rhyohtic lavas are usually spheruhtic, and show a banded or flowage 
structure, which is generally disposed at high angles. Elsewhere these rocks are finer- 
grained and massive. They are probably, in the main, intrusive. The breccias usually 
consist of fine fragments, although in places inclusions of fairly large size occur. Pumice 
is present in all these fragmentals. Both the lavas and breccias are altered, and in 
places considerably sihcified. Pyrite or its oxidized products are present throughout. 



77 

The segregation of the iron-oxides gives in many places a streaky and variegated appear- 
ance to the rocks. The auriferous deposits consist of — (1) Fairly well-defined fissure- 
veins ; (2) irregular pipes in breccia ; (3) zones of brecciated country, locally known as 
fonnations. Each of these will be described in connection with the various claims. 

Relatively high hills, faced in places by steep chfFs, rise on each side of the Tairua 
River in the vicinity of the mines, and permit of mining development by adit levels. 
In the neighbourhood of the Broken Hills and (iolden Hills mines the valley is narrow, 
but above and below it widens, to form somewhat spacious flats. 

The principal claims are the Tairua Broken Hills. Tairua Golden Hills, and the 
Tairua Monarch Consohdated. Other holdings are the Tairua Extended, Tairua Dawn, 
Tairua Leads, Tairua Reefs, Tairua Gem, and the Tairua Junction. 

The Tairua Broken IlilU Claim (area, 237 acres ; owners, Tairua Mines, Limited, 
Auckland). — This claim is situated on the eastern side of the Tairua River, about two 
miles above the post-office at Puketui, and around it most of the other claims are 
located. 

The claim was originally staked in 1895, on the gossan of an auriferous breccia- 
pipe above the workings now known as " The Caves." The property was acquired by 
the New Zealand Broken Hills Gold-mining Company (Limited), London, but the 
developmental work undertaken by this company was badly ])lanned and conducted, and 
in 1899 hquidation ensued and the property was sold. The claim was then purchased 
by Mr. H. H. Adams, on behalf of the syndicate which formed the Tairua Broken Hills 
Gold-mining Company (Limited). Initial operations were unsuccessful, but in 1901 
payable ore was located at the lowest adit, and the company entered upon a profit- 
raaldng period. The record* is as follows : — 

y Tons Yield. Value. 

eru.shed. Oz. £ 

1899 and 1900 .. .. 2,818 1,537 1,744 

1901-9 .. .. .. .. 27,804 49,025 8G,4G9 



Totals .. .. .. 30,622 5(),5fi2 88,213 

Dividends to the amount of £24,710 were paid. Early in the present year (1911) 
a reconstruction of the company was effected, in order to provide capital for subadit 
exploration, the adit-level ores opened being nearly exhausted. The new company is 
known as the Tairua Mines (Limited). 

The company's mill, which is conveniently situated close to the river, and connected 
by ground-tram with the main adit, consists of twenty stamps (850 lb. each) and a 
cyanide plant with the usual accessories, but it is somewhat out of repair. Water 
carried in a ground-race from the " Third Branch " of the Tairua operates the mill, and 
also the compressors, which transmit power underground. 

Access to the principal workings is afforded by the Battery level— an adit entering 
just above the horizon of the mill-hoppers, and only a few chains distant therefrom. 
Between the Battery level and the top of the hill, which is nearly 700 ft. liigher, four 
or five adits exist, but are not now used, and need not be further considered. From 
workings in the Battery adit a shaft-winze was sunk about 200 ft. on the imderhe of 
the Blucher reef, and from this ore wjis mined from two of the reefs at and above a 
depth of 80 ft. below the adit. As this shaft was badly placed, having regard to the 
southerly pitch of the ore-shoots, a vertical shaft was recently sunk about 360 ft. further 
southward ; and from it, at a depth of 120 ft., exploration is now proceeding. A new 
low-level crosscut nearly parallel with, and some 750 ft. southward of, the Batterj- 



• In a special report by Mr. John McCombie, dated January, 1910, the production figures are given as 
follows : " Up to the present 29,754 tons of ore have been dealt with, for a return of bullion valued at £90,677." 



78 

level, and at tho same horizon, has recently been driven about 500 ft. Its further 
extension will afford a much more direct access to the chamber of the new shaft than 
is now available. 

The rock throughout the whole of the lower workings consists of an altered flow 
rhyoUte, which nearly always shows banding and some spheruhtic structure. The altered 
rock contains pyrite, or its oxidation-products, and in many places is considerablv 
sihcified. Altered rhyoUtic tuffs constitute the rock of the higher horizons, but the veins 
were found either to give out in this rock or to be small and unprofitable. Small bunches 
of ore in mineralized pipes, however, occurred in these breccias, and will be referred to later. 

Numerous voinlets ramify throughout the rhyohtes, particularly in the vicinity of the 
main reefs. No pronoimced faults displacing the veins have been encountered, but minor 
displacements along puggy fracture -planes are not uncommon. 

The three types of auriferous deposits distinguished in the Tairua field are fomid 
in the Broken Hills Mine — namely, pipes, zones, and veins. Only the last named, 
however, have so far proved economically important. 

The pipe deposits are particularly irregular in outhne and erratic in ore-content, 
and are confined to the breccia formation. The material contained within their hmits 
consists of sihcified breccia, in which occur rusty selvages, numerous geodes and stringers 
of quartz, and irregular patches of a soft whitish kaohnic product. Pyrite is conspicuous 
in the less oxidized stuff. The richer material mined near the surface is stated to 
have shown, in addition, curly bluish sulphide streaks and some very finely divided free 
gold. 

It was, as already mentioned, the discovery of a small pocket of rich ore on the 
north side of the hill at or near the outcrop of one of these pipes that led to the 
original staking of the claim. Below this spot are the " Cave " excavations at No. 3 
level, from which about 2,000 tons of material was mined and milled, for a return of 
940 oz. of bulhon (value not recorded). The opencut and the two inner " Caves," 
which are connected by tunnels, appear to be on separate pipe-hke deposits of irregular 
outhne. The material mined and milled afforded no profit. 

Minerahzed zones or belts occur in several places in the mine. The most conspicuous 
is that intersected in the main low-level crosscut, and again, apparently, in the " Western " 
crosscut at the same level. In the main crosscut this zone is 38 ft. in width, and in the 
" Western " crosscut probably wider. It consists of banded rhyohte, highly sihcified 
compared with the ordinary mine-rock, frequently showing shattering and brecciation 
with kaohnic material in the interspaces, and is ramified by stringers of flinty quartz 
and by thin puggy selvages. This material everywhere carries a little gold and silver, 
but seldom exceeding in value a few shiUings (8s. or 10s.) per ton. This formation 
in the main crosscut strikes north-south and dips eastward. 

The fissure-veins have been responsible for almost the whole bulhon output of the 
mine. Those known as the Blucher, Night, Western, and No. 1 reefs have up to 
the present time proved the more important. The Punon, Welhngton, and No. 2 
reefs have been developed to a small extent, and have given a httle ore. A reef 
known as the New Year occurs in the southern part of the hill, and has been separately 
prospected, with only mediimi results. All of the reefs mentioned, in addition to others 
intersected, strike in directions not far removed from the north-south line. Towards 
the southern portion of the workings, however, a general convergence of the reefs is 
apparent, as the sketch will show. The dip of most of the reefs is to the westward, 
and usually at high angles. The walls of the vein fissures are, throughout considerable 
stretches, remarkably clean cut and well defined ; but in places a gradation from 
veinstone to wall-rock is apparent. The vein-material is characterized by the fhnty 
chalcedonic or opahne nature of much of the quartz, and by the presence of a large 



79 

proportion of rusty crushed and silicified country rock. Kaolinic material also occurs, 
but to a less extent than in some of the other reefs in the district. Shckensided 
selvages with puggy material and quartzose crusts along the vein-walls are common. 
These cherty quartz crusts show a banded structure, frequently carry high values, and 
occasionally show free gold. 

The Broken Hill fissure-reefs are not large, seldom exceeding 6 ft. or 8 ft. in 
thickness, and narrowing in many places to a few inches. 

In the four approximately north-south trending reefs^ — No. 1, Blucher, Night, and 
Western — which together have been accountable for practically the whole of the 
metal-output of the claim, the pay-ore occurs within shoots which are confined to a 
zone or belt of coimtry crossing them obliquely, or striking about north-e;ist. The 
shoots, moreover, all tippear to pitch to the southward at high angles. Within these 
shoots the richest ore usually occurred at the intersection of flinty stringers — more 
particularly the one known as Siever's leader — with the main reefs, or at marked 
bends in the reefs themselves, or at the locaUties where two reefs junctioned. It is 
noteworthy that the reefs did not persist up to the surface, but feathered out in the 
breccias which overlie the massive rhyolite. No pay-ore was found where the reefs 
intersected the breccias, nor, as a matter of fact, for some distance below the contact 
of the breccias and the rhyohte. 



New Short r^~7' 




PLAN 

Showing the various veins and 

productive zones ' Ore back to back 

in the Tairua Broken Hills Claim (Tairua) 

Scale of Feet 



The Blucher reef has proved the strongest and most productive ore-body in the 
claim. The width of vein-material stoped varied from 2 ft. to 8 ft., the boundary of 
pay-ore and worthless rock being in places only determinable by assay. From the 



80 

Battery level pay-ore was mined for a stretch of 325 ft. to 350 ft., and for a height of 
about 300 ft. At the intermediate, 80 ft. below the Battery level, the plans show 
stoping to have been done for a length of 180 ft. The shaft-winze, which follows 
the underhe of this reef for 200 ft. below the Battery level, was sunk near the northern 
boundary of the shoot, and from about the 65 ft. mark to the bottom is probably in 
low-grade or barren veinstone, as the shoot pitches to the southward. 

The Night reef afforded a shoot of highly remunerative ore at and above the 
Battery level for an average stope-length of 250 ft., and for a height above the level 
of about 200 ft. South of this main shoot, and separated from it by a stretch of 
75 fti. of worthless veinstone, a small shoot of ore occurs for a length of 105 ft. This 
small shoot is still intact, with the exception of an underhand stope which has been 
extracted below the floor of the main level. Lower down, at the 80 ft. intermediate level, 
the main shoot was taken out for a length of 180 ft., and from here upwards the 
stope-lengths gradually increased to the main level. 

The " Western " reef, which averages 3^ ft. in width, yielded ore for a stope- 
length of 120 ft. from the Battery level to a height of 160 ft. Above this the values 
fell below the profitable hmit. Below the level only one underhand stope was taken 
out, and the ore, erratic in value, was, on the whole, reported as payable. 

The No. 1 reef carried a shoot 270 ft. long, which was worked upward from the 
Battery level for an average height of 180 ft. At the Battery level its actual length 
was 180 ft. From here a winze was sunk 70 ft., and from an intermediate level 
driven from the bottom of the winze ore was stoped to the adit over a length of 160 ft. 
In general, the stope-lengths of the pay-shoots of the various reefs, judging by the 
sectional plans, attain a maximum either at or a short distance above the Battery level. 
No examination was possible below this horizon, but the stoping-blocks indicated on the 
plans are shorter at the 80 ft. level, worked from the shaft-winze. No assay plans 
have been kept, so that the variation in the tenor of the ore with depth could not be 
ascertained. 

The New Year reef, which occurs in the southern portion of the property, averages 
2 ft. in Nvidth. It has been prospected from two adits, and small patches of ore were 
found in which free gold was occasionally visible. A parcel of about 50 tons is stated 
to have returned approximately £1 8s. per ton. 

At present operations are mainly confined to subadit exploration from a vertical 
shaft simk from the Battery level in the southern end of the workings. At 110 ft. 
below the brace a level is being opened. This will command only small blocks (about 
30 ft. in height to the floor of the 80 ft. intermediate) on the Blucher shoot and the 
Night main shoot, but blocks practically intact to the Battery level on the Western 
reef and the Night southern portion. The No. 1 reef, about 360 ft. north-east from 
the shaft, has been worked down to the 80 ft. intermediate, and will not be further 
exploited mitil the proposed 220 ft. level is opened. 

The coimtry rock exposed in the shaft (110 ft. down) at the time of the survey 
was identical with that enclosing the ore-shoots on the adit level, and the same class 
of rock is said to persist to and below the bottom of the 200 ft. shaft-winze sunk 
further northward on the Blucher reef. Notwithstanding, therefore, that the stope- 
length of the shoots mined at the 80 ft. subadit level, judging by the plans, show 
a shrinkage compared with higher horizons, the prospects of mining pay-ore below the 
existing workings warrant the developmental work now in progress. 

On the Battery level itself there appear to be chances of shoots of ore existing 
in addition to those already worked. The limitation of the ores to stretches of some 
of the reefs crossing one (or, possibly, two) obhquely trending belts of country has 
not always received sufficient consideration in lajang out prospecting and develop- 



81 

mental work. The further extension of the drifts northward on the No. 2 and New 
Year reefs (intersected in the Battery crosscut eastward of No. 1 reef) to \\'itL'n the 
hmits of this belt offers reasonable prospecting chances. So, too. does exploration on 
the big mineralized zone, intersected in the " Western " crosscut, further southward 
than that already undertaken. 

In view of the fact that the various reefs appear to l)e trending towards a common 
junction in the southern and unexplored portion of the workings, and that reef-junct ons 
here frequently are found to be the locus of pay-ores, further prospecting in this direction 
is warranted. The extension of the now southern crosscut would considerably cheapen 
prospecting and developmental work in this direction. It would afford from the shaft- 
collar, and from any southerly extension of the workings on the adit level, a much shorter 
and more direct connection with the mill than the long circuitous one now available. 

Tairua Golden Hills Claim (area. 300 acres 3 roods 34 perches ; owners, the 
Tairua Golden Hills Mining Company. Limited. Auckland). — The Tairua Golden Hills 
is situated on the western side of the Tairua River, and south-westward of the 
Tairua Broken Hills Claim. Other adjoining properties are the Tairua Leads, the 
Tairua Dawn, and the Tairua Extended. 

The first discovery of gold in Lower Tairua (1893) was made in this claim, on 
what is still known as Davey's reef. Eleven tons of ore taken out by the prospector.'; 
yielded 47 oz. of bullion, valued at £141. Subsequent work at shallow adits, however. 
failed to reveal any continuation of profitable veinstone, and the claim was abandoned. 
Prospecting was renewed a few years ago, and in 1907 the Ta'rua Golden Hills Gold- 
mining Company was formed to explore the ground more systematically, with the 
result that at a lower altitude the existence of a strong reef, carrying ore, was proved. 
Davey's reef, which yielded outcrop ore, and other minor veins were found to have 
Uttle or no persistence in depth. 

Below the No. 2 level, in which the main reef was discovered. No. 3 level at an 
interval of 130 ft. has been opened ; and 254 ft. below this. No. 4 level, which has not 
)ct intersected the reef, is being driven. No. 2 level crosscut was extended to penetrate 
the hill completely, its total length being over 1,500 ft. No veins in addition to the 
main reef were intersected, but this tunnel serves to give access to a well-forested 
valley, from which all the timijer used in the mine and in the construction of the 
mill has been derived. 

The mill, which was completed about June, 1910. is situated oii the eastern side of 
the Tairua River, on the opposite side to the mine, and is connected with the mine at 
No. 4 level by an aerial tram. It consists of twenty stamps, four tube mills, and 
a cyanide plant. No provision has been made for amalgamation. The sliming of the 
whole of the ore is sought, followed by cyaniding in Brown-McMicken air-agitation tanks, 
filtering in Moore baskets, &c. Suction-gas generated from coke is the power employed. 

Up to the end of 1910 the company reports a partial clean-up of the mill, for 
bulUon valued at £253 from 650 tons of ore. 

The country- traversed by the reefs consists of altered banded sphcruHtic rhyoUte, 
similar to that of the Broken Hills Claim. The No. 4 adit crosscut penetrated soft 
altered rhyohtic breccias for some distance before entering the massive rhyohte, which 
is probably intrusive into these breccias. This rhyohte in the vicinity of the reefs 
is generally very hard, owing to advanced silicification. Beyond the reef-bearing area 
andesites are exposed just westward of the western entrance of No. 2 adit crosscut, which 
penetrates the hill. The main reef cut in the No. 2 and No. 3 levels strikes about 
N. 23° E., and dips to the westward at angles of from 70° to 80°. It is a fairly strong 
body of stone, lacking, however, the well-defined walls commonly associated with the 

6 — Waihi-Tainia. 



82 

Tairua Broken Hills reefs. Mineralization in the case of this Golden Hills reef appears 
to have progressed mainly from a median fissure into the wall-rock on either side. The 
width of ore mined varies from 3 ft. to 6 ft. 

Metasomatically replaced wall-rock is, as might be expected, abimdant. Much of 
the vein-formation, again, consists of angular fragments of altered rhyolite, cemented by 
a hght-greyish fUnty or chalcedonic quartz. KaoUnic material, of milky appearance 
when moist, carries a considerable proportion of the gold-silver content of the ore. 
This is particularly common in the sinuous median fissure already mentioned, and is 
also noticeable in subsidiarj- fissures and ca%'ities. An analysis of this kaohnitic material 
appears in another section of this report (see page .58). It assayed — Gold. ITdwt. 
15 <rr. per ton ; silver, 4 dwt. 10 gr. per ton. 

The veinstone considered payable is mainly confined to a northerly-dipping shoot, 
which in the levels opened — Nos. 2 and 3 — measures about 200 ft. in longitudinal 
extension. The richer material occurred in the sinuous kaoUn-fiUed fissure, and also, it 
is stated, where " cross-heads " or " fhnties " joined the main reef, these being more 
common on the foot-wall than on the hanging-wall. The slaty or gre^'ish-coloured 
flinty quartz, which in mcst other locahties in Hauraki is practically barren, carries 
here, at least in places, fair values. A piece of this quartz taken from the dump 
showed an assay value of £1 17s. 6d. per ton. Beyond the Hmits of the shoot men- 
tioned the drifts have been advanced some distance both northward and southward, and 
certain opencuts in the deeper guUies crossing the trend of the reef have shown 
quartzose material, which may indicate a still further extension of the main reef. Xo 
discovery of ore has, however, been reported from these prospecting operations. 

The proprietary company has not made known the assay value of the ore developed, 
and the mill returns are incomplete. The opinion is here ventured that the ore is, on 
the whole, low grade, and that only by a very considerable reduction in working-costs 
over those at present obtaining is there a prospect of turning it to profitable account. 

Tairua Monarch Consolidated Claim (area, 80 acres 3 roods 20 perches ; owners, the 
Tairua Monarch Consohdated Gk) Id-mining Company, Limited, Auckland). — This claim 
comprises former holdings known as the Triumph, Coronation, Conqueror, and Monarch. 
It covers a block of country lying on both sides of the Tairua River, between the 
" Third Branch " and Rhyohte Creek. On the Triumph portion exploration has been 
carried on almost continuously since 1901, while on the Coronation portion a httle 
prospecting was done between 1903 and 1906. Both the Conqueror and Monarch 
portions have been developed to a small extent within the last few years. The recorded 
yield from the claim is as follows : — 







Tons 


Yield. 


Value. 






crushed . 


Oz. 


£ 


1901-7. 


Triumph section 


.. 375 


311 


765 


1906. 


Coronation section 


. . 103 


23 


58 



Totals .. .. ..478 334 823 

Two small batteries stood on the claim at the time of inspection — one of two hea\n»^ 
stamps and two berdans on the Triumph (Taniwha), and one of five stamps and two 
berdans on the Coronation ; the motive power being an oil-engine and a steam-engine 
respectively. The Coronation plant has since been shifted and re-erected, and a small 
cyanide plant added to it. 

The vein -bearing rock is a flow rhyohte, exhibiting various phases of alteration. The 
less-altered rock is pinkish in colour, and frequently shows banding and spheruhtic 
structure. The more-altered country is softer and whiter, or, again, is highly siUcified. 
Rhyohtic breccias occur in several places, more especially in the Coronation ground. 



83 

In the Triumph portion of the claim the material crushod was derived from nuartz 
stringers and silicified bands, which outcropped on the top of the low hill to the south 
of the present workings. Rich seams occurred here, but when the material was mined 
in bulk it proved unprofitable. At present operations are mainly confined to adit 
workings on three parallel vein-formations. These strike in general a little to the east 
of north, and dip westerly at high angles. In the No. 2 level they are fairly well 
defined, but at No. 1 level they are more difficult to trace, and towards the outcrop 
apparently spUt into irregular quartz stringers in the siUcified country. At No. 2 level 
short shoots of ore, considered profitable, have already been opened. The amount of 
this material is diflicult to estimate, as the gold-silver content seems to be contained 
mainly in ramifying stringers of rusty or pyritous quartz — occasionally showing free 
gold — traversing sheeted and mineralized rhyolite. Veinstone is being mined over widths 
of 4 ft. or 5 ft. Judging by dish prospects and by assays of samples taken, the dis- 
tribution of values, as might be expected from the character of the vein-material, is 
erratic. Only bulk crushings can determine the value of the deposits. 

In the Coronation portion one or more indefinite belts or zones of luinoralizcd 
rhyolite occur, and have been prospected by various drives, cuttings, &c. From these 
the material mined and milled was derived. In the shattered and silicified zones the 
greater part of the gold-silver content appears to be associated with irregular small 
lenses and stringers of finely crystalline or Hinty quartz. KaoUnitic material occurs in 
places, and may also contain fuiely divided electrum. On the whole, however, the 
metal-content is low, and all attempts to work any of the formations at a profit have 
proved unsuccessful. 

Other Claims. — In addition to the claims already described, a number of prospects 
within the mineralized area of Lower Tairua are being worked by small companies. 

The Tairua Gem Company has driven a number of prospect! ng-crosscuts in the hope 
of locating any northerly continuation of the reefs of tlie adjoining Broken Hills Claim. 
Nothing of note has been discovered. 

The Tairua Leads Claim is staked on and around the jirominent siliceous sinter- 
deposits locally known as the " Big Blow," and occurring on the slopes of the hills 
rising from the western bank of the Tairua, nearly opposite the Broken Hills Claim. 
Assays of this sinter gave negative or negligible results for gold and silver. 

The Tairua Reefs Claim lies just to the north of the Golden Hills property ; and 
here an ellort was made to trace the westerly extension of the Golden Hills reef, but 
without success. Similarly in the Tairua Extended Claim the southerly extension of the 
sanie reef was sought. In the uppermost adit of this claim a vein of chalcedonic 
pyritous quartz has been cut and followed for a short distance, but it is said to be value- 
less. The tunnel just below this revealed a mineralized brecciated zone. 

In the Dawn Claim a number of indefinite stringers have been intersected. 

Gorric's workings, between the Dawn and the Extended ground, are said to have 
yielded a little gold in the earlier days of the field. 

The Neavesville Area. 

An area of country having a general elevation of 2,000 ft., and lying both on the 
eastern and on the western sides of Pakirarahi Mountain, has been the scene of mining 
operations from time to time since 1875. The mountain itself, which rises to a height 
of 2,578 ft., is the highest peak of the main water-parting of the peninsula, and lies 
at the head of the Puriri and the " Fourth Branch " of the Tairua. The small camp of 
Neavesville, on the Tairua side of the movmtain, is connected by a graded track with 
both Puriri and Tairua settlements. 
6*— Waihi-Tairua. 



84 

The value of the gold-silver output of the Ncavesville-Champion-Chelmsford area is 
in great part referable to the earlier years of the field, and is not recorded. From 1887 
to 1909 the statistics are as follows : Tons crushed, 190 ; bullion produced, 574 oz. ; 
value, £813. 

The rocks forming Pakirarahi, above a horizon of 1,800 ft. on the western side 
and above, say, 1.100 ft. on the eastern side, are rhyohtic tufis, altered and in places 
highly siUcified. At lower elevations greenish-grey andcsitic rocks of the " First Period," 
exhibiting varied phases of alteration, are exposed here and there, agencies of subaerial 
erosion ha^'ing here removed the overh-ing rhyoUtes. E\'idences of former intense 
hydrothermal action are widespread in the vicinity of the mountain. The rocks, both 
andesitic and rhyolitic, are profomidly altered (propyhtized), and some of the belts or 
zones of the rhyolitic tufis are so highly siUcified as to resemble a brecciated quartz. 
SiUceous sinters aboimd. These appear to have originally formed, in the main, super- 
ficial deposits of the " mushroom " type, but now exist as disjointed tabular sheets 
and angular fragments in the creeping waste of the mountain-slopes. The mineraUzed 
pipes and quartzose veins, which owe their origin to the same thermal waters, will later 
on call for further description. 

The physical configuration of the country has admitted of all mining being done 
from adit levels, but has rendered the equipment of some of the claims with crushing 
plants a costly imdertaking. 

At the present time mining is in progress on only two properties — namely, the 
Golden Belt and the Champion. Of the other claims, only the Chelmsford and the 
Ready BulUon need be mentioned. 

The Golden Belt Claim (area,* 333 acres 1 rood 18 perches ; owners, the Grolden Belt 
Gold-mining Company, Limited, of Auckland). — The Golden Belt Claim is situated on 
the eastern slopes of Pakirarahi Momitain, and is bounded to the westward by the 
Champion property. Mining operations have been carried on intermittently since 1875, 
some of the earUer operators making small profits. The older holdings were known as 
the Decide, Bonny Scotland, Golden Belt, Venus, and Golden Arrow. 

The present proprietary company, the Golden Belt, started operations in 1902, and 
equipped the claim \\\t\i a forty-stamp mill and cyanide plant, operated by water-power. 
An aerial tram about a mile and a quarter long connects the mine with the mill. In 
all, £46,700, including the value of the buUion extracted, has been expended in mine 
development and equipment by this company. 

The available figures are as follows : — 



1887-90. 


Decide Claim 


Ore. 

Tons. 

737 


Bullion. 
Oz. 
420 


Value. 

£ 
1.050 


1891-95. 
1894. 


Bonny Scotland 
McLiver Bros. 


.. 352 

7 


353 
41 


883 
103 


1894-95. 
1906-10. 


Gentle Shepherd 
Golden Belt 


11 

.. 8,256 


38 
7,246 


93 
14,616 



Totals .. .. .. 9,363 8,098 16,745 

The country rock of the upper levels of the claim is an altered fine-grained tuff, in 
the main rhyohtic, but containing a considerable proportion of andesitic material. The 
prevailing rock of the low level. No. 3, is of a pecuhar greenish-grey or bluish-grey 
colour, and its original character is completely masked owing to alteration. No remnants 
even fairly fresh, which would reveal its true character, are Adsible. It is probably, 

* This is the area of ground leased from the Crown. The company also possesses certain freehold lands. 



86 

however, the same andesitic or dacitic com2)lcx of flow rocks and breccias whicli is seen 
underlying the rhyoUtes on the western or Champion side of the mountain. None of 
the Golden Belt workings has yet been advanced within half a mile of the highest part 
of Pakirarahi. Here it seems probable that the old vent exists through which the rhyohtic 
material was ejected, so that a further extension of the low level may again disclose 
the tufaceous rhyoUte. 

The main reef of the claim is the Ajax, which strikes a few degrees east of north, 
and dips to the eastward at high angles. Another reef, the Britannia, exhibiting a similar 
strike and dip, has been fomid on the surface in rhyohtic country about 850 ft. further 
eastward, and near the Champion boundary, but practically no work has been done on it. 

The principal workings, which are confined to the Ajax reef, consist of three adit 
levels. The No. 3, or main crosscut, enters at an elevation of about 1,150 ft. Above 
this horizon No. 2 level is spaced about 150 ft., and No. 1, 255 ft. The vertical height 
between the No. 3 level and the surface-profile on the line of reef varies from 300 ft. 
to 650 ft. 

The reef has been proven for a horizontal distance exceeding 1,500 ft., and varies 
from a mere seam to 12 ft. wide. The markedly lenticular disposition of the veinstone 
when followed both in strike and in dip is a feature of the vein, and for this reason 
no close estimation of the amount of ore in any particular block is practicable. 

The vein-material consists of a sheeted and brecciated country rock of pecuhar 
greyish-black colour, more or less sihcified, considerably pyritizcd, and seamed with 
quartz veinlets. With this, white quartzose vein-fiUing often showing drusy cavities 
occurs as ribs and lenses. SiUceous re-cementation of brecciated and disjointed vein- 
quartz is in places conspicuous, and evidence of more or less continuous shearing along 
the plane of the vein is everywhere apparent. The foot-wall country almost throughout 
is shattered and frequently puggy, and so also is the hanging-wall, where the vein forma- 
tion attains its maximum widths. Slickensided fractures or " slidy heads " in places 
cross obhquely from one wall to the other, and give to the vein formation a pecuhar 
sphced effect. As may be supposed, substantial timbering is required throughout long 
stretches of the drifts, and treacherous ground is in places encountered in the stopes. 
Thus the costs of mining arc considerably increased. 

The stoping-blocks on the Ajax reef were almost wholly confined to the Nos. 1 
and 2 levels, the lowest level up to the present having yielded little or no ore. More 
settled coimtrj' and better-grade veinstone is, however, now being penetrated in the 
southern end of the low-level workings. 

Considerable importance was fonnerly attached by the Golden Belt Company to 
what is known as the " Bluiis " portion of the claim. Here occur enormous masses of 
hard sihcified rhyohtic tuff, bounded to the eastward by a bold scarp or hne of high 
cUffs. The material is identical in character with the "dyke" fonnation of the Champion 
Claim, on the western side of Pakirarahi Mountain, much of it being as hard as a rc- 
cemented quartzose breccia. Veinlets and bunches of drusy quartz occur throughout 
the mass, also iron-oxides derived from the weathering of pyrite. The hydrothermal 
solutions have also effected a sparse impregnation of gold and silver throughout a great 
bulk of this material. The writers are not disposed to beUeve that any systematic 
valuation of the minerahzed tuff has ever been made. Some quarrying has been done 
in one or two places, but it would appear that too much attention has been paid to 
secondary fractures where local enrichments have occurred. The returns from the tonnage 
treated are not available, but the scheme adopted for transferring the ore from the 
opencuts to the mill evidently precluded any chance of profit. 

It is generally beheved that there is a great amount of material in these " Bluffs " 
which Will assay from 8s. to 10s. per ton, the gold-silver electrum, which is worth about 



86 

£2 10s. per ounce, existing in a very fine state of division throughout the matrix. It 
possibly presents a very low-grade mining proposition, which may at some future time 
claim attention. 

Champion Claim (area, 142 acres 1 rood ;• owners, the Champion Mines, Limited, 
Auckland.) — The Champion claims are situated on the Pakirarahi Mountain, the main 
peak of the range between the headwaters of the Puriri and the " Fourth Branch " of 
the Tairua, Adjoining holdings are the Golden Belt on the Tairua side and the Ready 
Bullion on the Puriri side. 

Prospecting and mining has been done on this property from time to time since 
1875, but the gold-output referable to the earher years is not recorded. The present 
company acquired the property in 1906, and erected a ten-stamp mill, but the bulhon yield 
to the end of 1910 only amounted to 198 oz., valued at £745, the product of 1,330 tons 
of ore. 

The whole of the workings on the Puriri side of the divide are within the tufaceous 
rhyohtic formation, but the lowest adit level is not much above the andesitcs, which 
are seen outcropping in the creeks at or about the level of the battery-foundations. In 
addition to fragmental rhyohtic material, these tuffs appear in places to include a con- 
siderable amount of comminuted andesitic rock, no doubt derived from the older complex 
in which the explosive crater was formed. No definite quartz veins have been located 
in these workings, the so-called "dyke" and the Champion "reef" being merely por- 
tions of the tufaceous material which have been sihcified and otherwise minerahzed to 
a greater degree than the general mass of the formation. 

The " dyke " is a \vide band of the sihcified tuffs, which has a general trend of 
N. 30" W., and a dip to the westward at high angles. It was intersected in the Dayda^ra 
adit from the 165 ft. to the 250 ft. mark, measured from the entrance. A rise-connection 
was made here with a winze sunk from the surface in earher days. This old winze is 
stated to have followed for some distance a shoot of good ore, evidently a superficial 
enrichment in the " dyke " along a minor plane of fracture. WTiat is apparently the 
same "dyke" formation has been penetrated for 60ft. in an adit situated about 225ft. 
southward of the Daydawn. From the outcrop in the vicinity of the old ■w'inze men- 
tioned some open-cutting was done, and material worth from 8s. to 10s. per ton crushed. 
At the Davdawn crosscut the assay value over a width of 72 ft. is stated to average 13s. 
per ton, and similarly again at the Battery level, 70 ft. below this. At the latter horizon 
pyrite is more common, and the material is less amenable to treatment by amalgamation. 

The Champion " reef," 780 ft. north-east of the " dyke," is evidently an almost 
vertically disposed thermal pipe, which measured at the Dayda-iA-n level not more than 
20 ft. in cross-section, but was somewhat larger towards the outcrop. The soft earthy- 
looking tuffs Avithin its confines enclosed a network of veinlets of white crystalhne 
quartz, and carried a dissemination of granular and cubical pyrite. Filaments of free 
electrum (gold-silver) were occasionally visible, and not infrequently were associated with 
the small fragments of carbonized wood which the tuffs contain. The tonnage mined 
between the Daydawn adit and the surface was small, and prospecting - drives (the 
longest 165 ft.) radiating from the pipe at the adit level failed to locate any further ore- 
bearing pipes or veins. 

Between the " dyke " and the Champion " reef " the Daydawn crosscuts penetrated 
for a distance of 264 ft. a band or zone in the tuffs, which is stated to have shown, 
on samphng and assaying, gold-silver valued at from 5s. to 13s. per ton, with an average 
of 9s. Barren or practically barren tuffs separated this band from both the " dyke " and 
the " reef." 



87 

Oq the Tairua side of the range the Champion claims enclose a small V-shaped 
portion of the Ajax or Golden Belt reef, and this is now being stoped from the No. 1 
level of the Golden Belt workings. Prospecting adits and trenches have disclosed veins 
or silicified bands in the tuffs, but in none of these has an ore-shoot been discovered. 

It would appear that in the main section of the Champion considerable masses of 
the rhyohtic tuffs have been sparsely impregnated by wandering auriferous solutions. 
Apart, then, from small richer pipes — and others in addition to the one mined may be 
expected to exist — the area may possibly be found to present a very low-grade proposi- 
tion. A considerable amount of money has been expended on the property, and had this 
expenditure been intelligently directed accurate data as to the bulk and values of the 
low-grade auriferous material available could have been obtained. 

Ready Bullion Claims (area, 71 acres 3 roods 23 perches ; owners, private indi- 
viduals). — The Ready BuUion claims adjoin the Champion ground on the south side, and 
were formerly held by an Auckland company. 

The country rock is the tufaceous rhyohtic formation. As in the Champion, no 
definite quartz veins have been located, but bands in zones in the tuffs have been 
sparsely impregnated by auriferous solutions. 

An attempt was made to sluice the debris on hill-slopes bounding a snaall stream, 
but the supply of water available at this elevation was altogether inadequate. 

Chelmsford Claim (area, 100 acres ; owners, private individuals). — The Chelmsford 
Claim is situated in the upper and, in part, bush-clad slopes between the headwaters of 
Chelmsford Creek and the " Fifth Branch," both westerly tributaries of the Tairua 
River. The claim is, as the crow flies, about a mile and three-quarters east of Neaves- 
ville, and is connected with it by a horse-track. It was worked continuously by the 
Chelmsford Gold-mining Company, Auckland, from 1899 to 1905. during which period 
4,487 tons of ore was mined and cyanided for 3,144 oz. of gold-silver bullion, valued at 
£5,446. From 1906 to 1908 the Taihoa Gold-mining Company was organized to under- 
take further prospecting-work at the lower levels, but met with no success. A battery 
of ten light stamps and a cyanide plant still remain on the ground. 

The country rock of the claim is so highly altered that its original character is 
masked. In the main, it is probably a propylitized andesitic rock similar to that at 
the head of Chert Creek. The existence of cappings of rhyoUte is also to be expected 
in this locahty. The vein-formation evidently followed the period of rhyohtic extrusion. 
One main reef (No. 1) averaging about 2 ft. 6 in. wide, as well as a hanging-wall loop or 
branch vein, has been worked, and some three other veins are reported to have been 
found. The No. 1 reef strikes north-south, and dips eastward at high angles. Four adit 
levels gave access to the workings, and covered a maximum vertical range of 350 ft. The 
outcrop ore carried a gold-silver content averaging about £5 per ton, but the rate of 
impoverishment from the surface downward was rapid, and throughout the block worked 
the ore won yielded on treatment an average of less than £1 5s. per ton. The stope- 
length on the main shoot, which was disposed vertically, measured about 150 ft., and 
httle ore was mined below No. 2 level, 150 ft. from the highest point of outcrop. A 
minor block, about 80 ft. long and some 160 ft. north of the main shoot, was also stoped 
from No. 2 level to the surface. 

The vein-material, as far as could be observed, consists mainly of sheeted and 
brecciated country, re-cemented by quartz of rather flinty or chalcedonic character. Geodes 
lined with quartz crystals are not uncommon. The veinstone seems to have been all 
oxidized, and much of it is stained rusty and black with oxides of iron and manganese. 

The following assay of typical vein-material serves to show the ratio in which the 
two precious metals occur: Gold, 1 dwt. 5 gr. per ton; silver, 4 dwt. 10 gr. per ton. 



88 

Tliu workings are now mostly inaccessible, but from all accounts the prospecting- 
work done at the lowest level by both the Chelmsford and Taihoa companies gave 
Uttle or no promise of pay-ore being found. 

" Fourth Branch " of the Tairua River. 

A number of small veins and mineralized zones occur in tributaries of the " Fourth 
Branch," but samples taken from these during the survey carried only small values, or 
were quite barren of the precious metals. The best-defined vein observed outcrops in a 
headwater branch of Battery Creek, and appears in the creek-bed for about 14 ft. This 
vein, which is about 4 ft. 6 in. wide, strikes about N. 25° W. and dips almost vertically. 
The vein-material consists of soft puggy mineralized andesitc, through wliich ramify 
stringers of quartz and seams of granular pyrite. An assay of a representative sample, 
however, only yielded — Gold, 1 dwt. 18 gr. per ton ; silver, 2 dwt. 12 gr. per ton. 

The Tairua Valley above the " Fourth Branch." 

The upper valley of the Tairua, with its numerous tributaries, shows in several 
places quartz veins, sintery deposits, and puggy minerahzed zones. None of these has 
given, where prospected, any encouraging results. They have their greatest development 
in the neighbourhood of " The Wires " and in the valley of the " Fifth Branch." 

At " The Wires " a number of quartz reefs may be seen, and also an extensive 
siliceous sinter-deposit, which trends eastward from the Tairua to the headwaters of the 
Wharekawa. Prospecting-work in the form of shallow adits was done on certain of these 
reefs during the period of the mining " boom," but the area is now abandoned. The 
reefs occur in highly altered andesites and overlying rhyohtic tuffs and breccias, are 
narrow, and consist mostly of rather vitreous quartz, carrying coarsely crystalhne pyrite. 
The assays made from a number of these reefs gave very low results. 

In the " Fifth Branch " of the Tairua River a number of more or less definite reefs 
and stringers exist. Most of these occur in propylitized andesites, but one at least 
cuts altered rhyohtes, which here intrude or overlie the andesite. Dish prospects and 
assay-results seem to warrant further exploration of several of the reefs appearing in the 
main " Fifth Branch " and some of the stringers traversing its tributary, Pyrite Creek. 
In the " Fifth Branch " itself, just above the mouth of Pyrite Creek, a mineralized 
zone about 12 ft. wide, consisting of highly pyritized propyhte traversed by stringers 
of quartz, occurs, and its material gives, on washing, small quantities of gold. Several 
defined though somewhat narrower reef-formations are seen higher up the valley. All 
of these are of the same nature as the larger ones described. In Pyrite Creek the 
stringers mentioned appear just below an old timber dam. The widest of these shows 
about 1 ft. of pyritous quartz, associated with much minerahzed country. The highest 
results obtained from assays of samples collected in this locahty showed — Gold, 7 dwt. 
14 gr. per ton ; silver, 5 dwt. 1 gr. per ton. 

Ohui. 

At Ohui the area of inineralization within wliich isolated prospects have been 
located measures about a mile and three-quarters by half a mile, and its limits are 
quite uidikely to be extended. This strip of country, which is bomided to the north 
by Ohui Creek, rmis nearly parallel to the long sandy Ohui-Wharekawa beach, and is 
distant about a mile therefrom. Topographically it consists of low hilly comitry, incised 
by small creeks meandering through relatively broad swampy valleys. 

The earliest gold-discovery in Ohui was made in the old Nell Claim by Mr. James 
McGregor in 1893, but subsequent developments proved disappointing. Later, outcropping 



lb cuxompany SuUetin N" 15, 



Just in Timj? 

S.Q.C. \ V , ISO. 1.28 



J'/-"' 



Star of Tairua 

S.Q.C. 



100. „^0. 0. 



^t^'^^" 



Golden Bug ^ 

, 100. 0. jj 



iTM Tairua /Keefs 



i? 



Dawn of Hof 
sac 

100. 0. 



Golden Run S.Q.C 

93 3. 23 



' Broken Hills 1^4 S.' 

■r' 

70. 3. 26 



Battery 



Broken /yHuLs S.C. 




'^so\ 



: Tairua /GoldenI Hills 



\Di<r 



al'SSM 



/Brok&i< Hills N? 2 , 




2 4 */ Tairua South S.Q.C 



,„,-i"... 



Tairua Golden Hills J 



Site 
5.0.0 



69 3. Zf 



7*- 

TairXja Blucher S. b.C' 



H 6S 0. 38 



I *, /li/T T;;U* lAiRUAf Monarch h^// / r 



o>i" 



VV.,»i ^ 



/ 






Monarch 

I Smithy ■ 

1 *iow_Ut£lJ 





/ Coronation S.Q.C- | Coronation Ext? / /"^i 
'/^ 7s. z 04 [ 75 2. 2s I /J /i 

^' ^ ' ^ \ / // .# 

Coronation ! \ \ J ( '^ <P^ 

I — /-■< i \l/—/ J ^'^ 



Map of the Lower Tairua Mining Area 

Showing geological formation, mining claims, principal reefs &c. 



— Reference to Geolo g ical Colours - 

Andesite.' Second Period 

Rh^olltlc lavas & tuffs' 'Third PeriodI | ~ 

Recent |/-'"\-:'.'.V:>v 

Quartz veins, .. [ yj j^ Sinters | oOOo~ 



Scale of Chains 



10 5 



Q.E.H. 



8y Authority : John Maokay, Qoutrnmant Printer 



89 

veinstone was lociited on ground afterwards acquired l)y tlic Maori Dream Gold -mining 
Company (Limited), London, and situated about 70 chains south of the old Nell 
workings. The English company iidded a few surface drives to those already constructed 
by the prospectors, and also made an rmsucccssful attempt to sink a shaft, but the capital 
expended did not materially advance prospecting exploration on the claim. The Phoenix- 
Dreadnought includes the older Waihui, Maorilander, Harp-of-Tara, and Last Chance 
claims, and has been prospected intermittently since 1S'.)5. A good deal of "fossicking" 
has been done by different owners, and a shaft 90 ft. deep was sunk by the Phoenix 
Company in 1907-8. On the wliolc, however, the capital expended here gave no 
commensurate results, and has afforded few data on wh'ch to base a conclusion as 
to the prospective value of the several holdings. 

The total recorded }neld of Ohui to the end of 1910 is — Tons crushed, 109 ; bullion 
produced, 218 oz.; value, £570. 

The vein-bearing rocks of Ohui are both biotite-rhyolites and " Second Period " 
pyroxene-andt'sites. The rhyolites are the yomigcr, and liavc been extruded through 
the andesites. Pumiceous tuffs have a widespread development ; but the quartz veins 
appear to have no extension into these rocks. The Pha'uix area has evidently been 
the locus of great hydrothennal activity, and is probably near the sit« of one of 
the conduits or craters from which the rhyolites were extruded. SiUcccuis sinters, 
the deposits of ancient hot springs, aboiuid, forming resistant cappings on several of 
the prominent knob-like hills. These sinters are. as at Kuaotunu and elsewhere, largeh' 
of the mushroom type of deposit, and arc unlikely to persist to any considerable depth. 
The disposition of the vein formations appears to show but little conformity with 
the trend of the surface outcrops of these sinters. 

Topographically the coujitr}- is one of mild relief, especially in the vicinity of 
the known vein formations. Adit levels command Uttle " backs," and therefore 
systematic prospecting means the judicious expenditure of capital. Swamps encroach 
a considerable distance up the valleys of the small streams draining the area, yet 
the amount of water encountered in the Phoenix shaft-workings which were below the 
swamp-level was not great. The existing claims in the field are the Phoenix, the 
Dreadnought, and the Great Mexican. 

Phanix Claim (area, 56 acres 3 loods; owners, tlic Phoenix Gold-mining Company, 
Limited, Auckland). — The Phoenix Claim is situated in the southern portion of the 
Ohui auriferous area, in the vicinity of the conspicuous sinter hill. The principal 
workings are distant, as the crow flies, one mile from the shore-hne. The graded 
road which leads from the sand-dunes of the coast-line across the low hills and swamps 
to the mine shaft is I mile 15 chains in length. The claim includes the older 
holdings — Waihui, Maorilander, and parts of the Last Chance and the Harp-of-Tara. 

Prior to the Phoenix Company starting operations all the work was confined to adit 
levels. Small erratic pockets and lenses of ore were found in the vicinity of outcrops 
of sihceous sinter, but the backs available were small, and no continuous run of ore 
was fomad. 

The Phoenix Company started operations in 1908, and, in addition to doing some 
surface prospecting, sank a shaft, and did a small amoimt of work down to a depth of 
80 ft. The total recorded output to the end of 1910 is 26 tons crushed, for bullion valued 
at £125. 

The mine-equipment consists of a small vertical shaft with two compartments, 
each 3 ft. 6 in. by 3 ft. 4 in. ; one for pump and travelUng-way, the other for hoisting. 
The pump — plunger type, which is of miniature proportions — is operated by a producer- 
gas engine, whilst the hois ting- winch is worked by a kerosene-engine. 



90 

The principal vein-bearing rock of the claim is a spherulitic biotite-rhyoUte ; but, 
as the map will show, older pyroxene-andesites outcrop as a north-east trending belt 
in the vicinity of the workings. The rliyolites are every^vhere considerably altered, 
and in places highly sihcified. The aiidesitic belt, in marked contrast, shows a considerable 
amount of hard, dark, relatively fresh rock, and alteration is apparently confined to 
its contact with the rhyoUte and to local zones of fracturing. The question as to 
whether or not the rhyolite is continuous south-eastward of the shaft beyond the 
10-chain mark, and on the strike of the vein formation, is doubtful, owing to the 
absence of outcrops. If existing here, it may be found either to intrude the andesitic 
belt or to overUe a depression in the andesites. It may be added that elsewhere the 
mapping of the boundary between the two rocks is only approximate, owing to the 
absence of outcrops. The rtyoUtic area surrounding the shaft, and extending south- 
west to the Phoenix (sinter) Hill, encloses numerous cappings and deeper-seated sheets 
of siUceous sinters, and, as mentioned before, is probably tlie locus of a thermal crater. 

Mining from the shaft is confined to levels at 40 ft. and 80 ft. below the brace. 
These reveal a sihcified band in the rhyoUte, striking about north-west. The width of 
this band has been proven for at least 65 ft. without its Umits being reached ; but the 
value of the formation as a whole has not been determined. From information 
gathered** the mineraUzed band appears to be a zone or belt of sheeted rock-fracturing 
and brecciatiou, along which siUcification and, to some extent, ore-deposition has taken 
place. The two ore veins worked are enclosed in this wide band, and are in aUgnment 
\\4th its trend. One of these is vertical, and strikes througli the shaft ; the other 
is 40 ft. north-east of the shaft, and dips towards the first-mentioned vein. It is 
stated that between these two veins several minor streaks carrjing ore exist, and, 
further, that another 100 ft. of sinking should reach the junction of all these converging 
veins. 

The ore vein passing through the shaft is reported to varj- from 1 in. to 2 ft. in 
width, with an average width of 7 in. It has been driven on for about 200 ft. in all 
— 90 ft. north-west of the shaft at the 80 ft. level, and 110 ft. south-east at the 40 ft. 
level. In the latter direction it was fomid to intersect, at from 90 ft. to 110 ft. from 
the shaft, a transverse quartzose reef, and 20 ft. beyond this it was followed to a band 
of faulted rock trending parallel to the cross-reef. 

The ore vein existing 40 ft. to the east of that described is reported to range 
from 12 in. to 14 in. wide. 

The auriferous veinstone is a milky - white quartz showing pronoimced ribbon- 
structure, and carrying in fractures films of iron and manganese oxides. Sugary 
quartz and replacements after calcite are not uncommon. Remnants of pyrite occur, 
also spots and curly films of a finely granular bluish-grey sulphide — apparently argentite. 
Free gold is occasionally visible in the oxidized ore, also in association with the 
granular sulphides. 

A parcel of 13 tons of ore from the shaft- workings was despatched to Thames for 
treatment, and gave a return of £5 13s. per ton. It is beheved that a considerable 
proportion of the " fines " of the ore, which usually carry the higher values, was lost 
in transit. A general sample, showing no visible gold, was taken by the writers from a 
small heap of dump ore. This sample yielded on assay — Gold, 2 oz. 16 dwt. 1 gr. ; 
silver, 7 oz. 16 dwt. 7 gr. : value, £11 19s. 9d. per ton. 

* The workings were inaccessible at the time the survej' was made, owing to cessation of pumping 
operations. The following is culled from the Mining Inspector's report, C.-3, 1909, page 20 : "A drive 
was started with the object of cutting the r^f to prove its width : at the time of my visit nearly 100 ft. 
of reef formation, with its ribs of country rock and quartz alternating, was showing." 



91 

The 20 ft. cross-reef which was cut in the drift at the 40 ft. level south-east of the 
shaft is reported to have given some ore where intersected by the smaller vein ; ore 
to the amount of 10 cwt. treated at Thames yielding at the rate of £2 lOs. per ton. 
No work was done beyond the hmits of the drift. 

The sintery quartzose bands outcropping on the surface and in small drives and 
opencuts were sampled and assayed, but in no case afforded more than a few grains 
of gold and silver to the ton. An analysis of the sihccous sinter forming the capping 
of Phoenix Hill has been submitted in a pre\'ious chapter. (See p. 61.) 

The quartzose formation, which trends in a crescent-shaped manner, and has been 
followed in a surface drive situated about 10 chains south-cast of the shaft, gave on 
assay only 1 gr. of gold to the ton ; but pannings showed a colour of gold here and 
there in the clay-lined fractures. 

As regards the future prospects of the Pha-nix Claim it is diflicult to speculate, 
as no examination of the shaft-workings was possible. The fact that practically 
barren sinter-deposits give place below the surface to siUcified bands enclosing parallel 
veins of sulpliide ore, which arc stated to be increasing in value and converging in 
depth, is a promising feature. The claim, notwithstanding the amoimt of money 
expended, is as yet merely a prospecting proposition. Any further work in adit 
levels is certainly to be deprecated, but the judicious expenditure of further capital 
in prospecting at horizons deeper than those yet explored can be counted a legitimate 
venture. 

The Dreadnought Claim (area, 100 acres ; owners, the Tairua Dreadnought, Limited, 
Auckland). — This claim bounds the Phmnix Claim to the west and south-west. The 
rock exposed in all the small prospecting-drives is an altered spheruUtic rhyolite. The 
work done has revealed nothing worthy of note. Guidance for further operations can 
only be afforded by the results which may attend deeper-level exploration in the adjoining 
Phcenix Claim. 

The (ileal Mexiean Claim (area, 55 acres and 26 perches ; owners, a private 
syndicate). — This claim bounds the Phcenix to the northward, and includes the original 
Maori Dream property. No workings exist other than the old adits on the Maori 
Dream reef, and most of these have collapsed. The Maori Dream reef outcropped on 
the low foot-hills which border the swamp, along which passes the graded road to the 
Phoenix shaft. The country rock of these foot-liills in this locality is a pyroxene andesite, 
completely altered in the vicinity of the reef, but elsewhere showing Uttle or no alteration. 
Small ore-dumps still remain at the mouths of the old adits. The veinstone is a rust- 
stained hard white quartz, much of which shows a curly banded structure similar to 
the Pha>nix ore. Remnants of pyrite are observable. Some of the blocks of stone 
exceed 1 ft. in diameter, suggesting a fairly strong vein. An average sample collected 
for assay yielded — Gold, 11 dwt. 8 gr. ; silver, 1 oz. 2 dwt. 17 gr. : value, £2 7s. 7d. 
per ton. 

The ore treated totalled 23 tons, and was distributed as follows : 1894-95 — 2 tons 
(Thames School of Mines) returned £57 16s. 9d. ; 6 tons (Kuaotunu), treated by amal- 
gamation), £6 6s. per ton, £37 16s. ; 15 tons picked ore shipped to London, worth, it 
is said, £15 per ton, £225 : total value, £320 12s. 9d. 

The vein, it is stated, ranged to 4 ft. in width, and averaged about 15 in. It 
presented a low angle of dip, was wavy and in places even flat-lying. The inclination 
was somewhat greater when followed down near the edge of the swamp. In this 
direction, it is stated, the reef was lost, or could not be located ; but no real attempt 
was made to prove its downward continuation. 



92 

Mineralization in this locality appears to have followed a flat-lying sinuous fracture, 
dipping more steeply, however, towards the southward. Where the vein was practically 
flat-lying, hard relatively Uttle-altered andcsite was foiuid in places to underlie it almost 
directly. The shoot of ore v\as about 100 ft. long, and gold was frecjuently seen in 
tlie oxidizing sulphide seams. A feature of the veinstone was the occurrence of a 
narrow wavy band containing flinty and white soapy materials. This band migrated from 
one side of the reef to the other, and with it rich ore was almost invariably associated. 

The swamp lying immediately southward of the workings measures from 7 to 10 chains 
in width, and it is probable that erosion has here followed an area of softer altered rock. 
It is in this direction, therefore, that the counterpart of the reef should be sought at 
greater depths. 

Wharekawa Valley. 

The Wharekawa River, flowing into Wharekawa Harbour on the eastern coast-hne, 
drains a considerable area of comitry in the south-eastern portion of the Tairua Survey 
District. No mining prospects were discovered within its confines prior to 1895, but since 
that year both Enghsh and local capital has been expended in prospecting and develop- 
mental work on several claims. Of these claims only the Luck-at-Last, worked by the 
AVhangamata Proprietary (Limited), of London, and the Phoenix-Pukewhau and Wai- 
mangu, worked by Auckland companies, have contributed to the metal-output. Statistics 
show that up to the end of 1909, 10,781 tons of ore was crushed, for bulhon valued 
at £17,871. No dividends have been paid by any company which has operated in 
Wharekawa. 

The rocks of the valley are andesites and dacites of the " Second Period," overlain 
and intruded by rhyohtes of the " Third Period." Quartz veins and sihceous sinter- 
deposits have fairly extensive development, but metallization of any importance is 
confined to local areas of rock-alteration. Although the veins which have afiorded ore 
occur in the andesites, their origin, as well as that of most of the barren veins and 
sinter-deposits, is referable to the eruptive " after-actions " connected with the extrusion 
of the rhyohtes. 

The physical configuration of the country has up to the present admitted of all 
mining operations being conducted from adit levels, but in the Luck-at-Last Claim the 
lowest adit practicable is now being driven. 

The claims in existence number two, the Luck-at-Last and the Goldwin (old 
Waimangu) ; and of the abandoned claims only the Phoenix-Pukewhau need be mentioned. 

The Luck-at-Last Claim (area, 100 acres ; owners, the Luck-at-Last Gold-mining 
Company, Limited, Auckland). — This claim covers portion of the high ridge which rises 
from the eastern side of the river below the junction of Inca Creek. It is coimected 
with Whangamata Harbour by a road about six miles long. 

The earhest discovery of gold in the "Wharekawa was made on this claim by 
Messrs. Abbott and Withers in 1895, and 1 ton of ore from what proved to be the 
main reef pelded bulhon valued at £15. The property, \\'ith adjoining claims, aggre- 
gating in all 294 acres, was then acquired by the ^Vhangamata Proprietary (Limited), 
London, which, after doing prospecting and developmental work, erected a mill consisting 
of two Blake rock-breakers, one ore-drier, three No. 5 Krupp mills, twelve 20 ft. cyanide- 
vats, and six berdans, all operated by water-power. Crushing was commenced in 
June, 1899 ; and, up to the end of 1901, 10,765 tons of ore was treated, for 13,176 oz. 
5dwt. of bulhon, valued at £17,666 16s. 9d. In 1902 the property was sold by the 
company, and in the follo'wing year the whole of the plant was removed and the 
claim abandoned. In 1909 the present company commenced operations, and is driving 
a low level to intersect and further exploit the reef at greater depth. 



7b actMmpany Bulletin J^" 15, 




Phcenh Mill "^ ^"'Off^c/ smters 






, - '^+ tlesthered andesHe in trem 
Sinter bmjtders abput 
but probably erritics^ 




-" 


=—!-:< 


0) 

■ • ■ 
••■<»■ 




it ' '. 





Map of the Ohui Mining Area 

Showing the geological formation of the country including the 
PhcBnix and old Maori Dream Claims. 



Reference to Geolo g ical Colours 

Flow Andesites,all 'Second Period!. 

Rh^olite-flows a breccias. 'Third Period_'_. 
Recent 



S MACKINTOSH B 



Scale of Chains 



Quartz veins.. _ [ y^ \ Sinters. 



^^.■■'■■■<\ 



10 5 

' ■ ■ ■ ' I 



20 



By Authoriti) : John Mackay, Gouernwent Printer 



G.EM. 



7 GO. a. /e 384-. 



93 

Access to the mine-workings opened by the AVhangamata Proprietary was afforded 
by three adit levels: No. 1, 20ft. to 177ft. below the vein outcrop; No. 2, 77ft. 
below No. 1 ; and No. 3, 200 ft. below No. 2. A shaft was sunk from near the outcrop 
with a view to deeper-level exploration, but it was not carried below the No. 3 adit. 
Connection was made from this shaft with the three existing levels. 

The country rock throughout the whole of the workings is a pyroxene dacite in 
various stages of alteration and weathering. That in which the alteration is less 
advanced is a hard, rather flinty and patchy- looking, greenish-grey rock, shoAving small 
glistening feldspars and dispersed ferro-magnesian minerals. A flow structure is faintly 
observable. The weathered equivalent of tliis rock strongly resembles a banded rhyolite, 
owing to its pinkish-grey colour and the markedly streaky structure developed. The 
completely propylitized rock in the vicinity of the reef differs in no respect from that 
afforded by a nonnal andesitc. 

Only one reef, with minor branches or loops, has been located, and it seems unlikely 
that other reefs exist. This reef, which strikes N. 20° K., and dips at high angles 
to the eastward, ranges from 1 ft. to 17 ft. in width, and throughout the stoping- 
blocks averaged about 5 ft. 

The vein-material consi.sts of a finely crystaUine milky-white quartz, with lenticular 
inclusions of propyhte, but where examination was possible (this was outside the limits 
of the pay-shoot) it contained Uttle or no pyrite or other sulphides. The vein-walls 
are, on the whole, fairly well defined, but in places gradation from veinstone to wall-rock 
is observable. The vein has been explored by long drifts at each of the three levels, 
but the pay-ore was confined to a single shoot, which it is said had a stope-length of 
about 300 ft. The ore was friable and easily mined. 

The English company ceased operations after exhausting the blocks in the No. 3 
and shallower levels, and the present owners are driving an adit crosscut to intersect the 
reef 160 ft. below the old workings. The following statement appeared in the New 
Zealand Mines Report of 1900 : " In the main (No. 3) adit the country is considerably 
tighter than in No. 1 and No. 2 levels. The reef is of a harder nature, and is spht up 
in places, the country rock intervening." * An examination of the No. 3 level crosscut 
shows that the belt of softer countrj- — namely, the belt of" advanced alti^ration — is 
considerably narrower than at shallower horizons, although even here it measures 100 ft. 
on the foot-wall side and 300 ft. on the hanging-wall side of the reef. The No. 4 level 
may be expected to show a still narrower channel of propyhte, with probably a reduction 
in the average width of the veinstone. In strike the reef weakens south of the crosscut, 
and at 250 ft. is a mere seam. On tliis stretch no pay-ore was obtained. Northward 
of the pay-shoot, but at an undetermined distance, the reef-bearing andesitc gives place 
to biotite-rhyoUte, which is seamed with quartz veinlets and silicified bands. The 
Luck-at-Last vein fissure weakens and dies out in this rock, and this fact accounts for 
the failure of the companies that owned the northern claims to locate the main reef. 

Goldwin Claim (area, 100 acres ; owners, private individuals). — The Goldwin Claim 
is situated in the headwaters of the \Vharekawa River, above the junctions of Culpan's 
and Sutchffe's creeks, and near the old telegraph-hne known as " The Wires." 

The claim includes portions of the older Waimangu and Pha?nix claims. The 
Phoenix portion was prospected by an Auckland syndicate (the Phoenix-Pukewhau) from 
1895 to 1897. As the result of operations, 14 cwt. of ore was sent to Thames, and 
treated, for bullion valued at £14 4s. 2d. In addition, a few small parcels of similar 
ore are said to have been subsequently shipped to Austraha. The Waimangu portion 
was worked by the Waimangu Company from 1904 to 1908, during which time 13 tons 



* C.-3, 1900, p. 83. 



94 

of j)icked ore was packed and carted to a mill, for returns totalling £136 10s. Id. A 
small tonnage of oxidized ore of fair grade was left on the claim dumps, as the expense 
of transit to the nearest battery was high, and the company evidently did not consider 
that the potentialities of the claim warranted the erection of a mill. 

The rocks of the Goldwin Claim are hornblende-hypersthene-andesite lavas and 
breccias, locally altered by hydrothermal action. Thin cappings of pumiceous rhyohtic 
tufi, however, occur here and there, being the mere residuals of a once much more 
extensive development of these rocks. Siliceous sinters are common, and are referable 
to the hydrothermal action which followed the extrusion of the rhyohtes. So, too, are 
probably the quartz reefs about to be mentioned, although these occur in the andesites.* 

The workings of the Phoenix portion of the claim, which appear to be confined to 
one reef, were mostly inaccessible. This reef, where visible, ranged from Sin. to 2ft. 
wide, and had a strike of about N. 45° E. The veinstone is a massive and banded 
finely crystalline quartz, with rusty streaks due to the oxidation of sulphides. The 
little gold obtained by panning was observed to exist in a very fine state of division. 
As the ratio of silver to gold in the bullion was about 6 : 1, it is probable that the 
sulphides carried argentite. It is stated that the small run of ore mined was situated 
near the junction of a branch vein with the main reef. The prospecting operations were 
conducted on a small scale. 

In the Waimangu portion one reef only has been located. It has been exploited 
from three different adits and a few small opencuts, which in all cover a vertical 
range of not more than 150 ft. The No. 3 adit is practically the lowest obtainable, 
being but httle above the level of the creek-bed. 

The reef strikes about N. 30° E., and dips to the north-westward at angles approxi- 
mating 70°. In No. 2 level the length of the drift is about 85 ft., and in the upper 
level somewhat less. The low level was only partly accessible, but, beyond a hmited 
amount of drifting and a rise-connection to the No. 2 level above, httle work has been 
done. The width of veinstone extracted varied from 2 ft. to 4 ft., but the vein 
formation is usually wider than this, and its foot-wall has seldom been exposed below 
the outcrop workings. 

The ore, which is practically all oxidized, consists of wavy, banded, and massive 
finely crystalhne quartz, in places showing considerable brecciation and re-cementation. 
Stainings and seams of pecuhar purphsh and chocolate colour in some of it represent 
the oxidation-products of the richer of the sulphides, and along these seams the ore 
frequently sphts and exhibits finely divided " gold " or electrum. Picked ore of this 
description has returned over £40 per ton. 

The low level revealed a harder and more vitreous brecciated veinstone, carrying 
httle gold and silver. The country rock (the hornblende-hypersthene andesite) is also 
harder here than in the upper levels, and the range of propyhtization appears to be 
restricted. The section, moreover, exposed in the creek on the hanging-wall side of the 
reef shows mostly hard rock, ^\^lere the creek cuts across the southerly trend of the 
vein — about 8 chains from the workings— there is no sign of the vein fissure, heavy 
breccias constituting distinctly unfavourable country being noticeable here. The reef 
would appear to be of hmited longitudinal extent — at least, in a south-westerly direction. 
Towards the north-east the alteration of the intrusive rhyohtes at the head of No. 1 
Creek, where some old prospect drives are to be found, suggests the continuation of a 
hne of minerahzation through the unprospected spur between Culpan's and No. 1 creeks, 
both of which carry a httle detrital gold. 

* No rhyolites now overlie the andesitea in the particular localities where the reefs occur. 



96 

Had the Wa'inangu reef existed in a more accessible locality it is certain that 
more ore would have been mined from the adits opened. The prospects of mining 
below the creek-level, however, do not appear promising. 

Whangamata. 

In the Whangamata district, where prospecting has been carried on intermittently 
for over twenty-five years, numerous isolated prospects have been located. These were 
connected with quartz veins in andesitic rocks, or with " blows " and bands of siliceous 
sinters in rhyoUtcs. 

All of the claims which have jnelded ore occur ^v^thin the valley of the Te Moanuanu 
or Wentworth Stream, where quartz veins are found enclosed in propylitizcd andesites 
(" Second Period " volcanics). Several veins are known to occur in the valley of the 
Wairoa Stream, but prospecting:- work on them has failed to reveal ore. The siliceous 
sinters have their greatest development on the dividing range between the Wairoa and 
Whangamata streams, and, again, on the long peninsula extending from Whangamata 
Inlet to the mouth of the Wharekawa Stream. Numerous prospecting-trenches arc 
visible, but nothing affording payable ore has ever been located. 

The only claims which warrant description are the Auckland (Wentworth) and the 
Glamorgan. 

Auchland Claim (area, 349 acres 2 roods 37 perches ; owners, private individuals). — 
The recently abandoned Auckland Claim, formerly known as the Mananu and, again, 
as the Wentworth, is situated in the upper part of the valley of the Wentworth or Te 
Moanuanu Stream, flowing into AVTiangamata Harbour, and is close to the Whangaraata- 
Hikutaia Road. 

The ground was worked almost continuously from 1897 to 1908. The Hauraki 
Peninsula Exploration Company (Limited). London, undertook the initial development, 
and organized the Mananu Gold-mining Company to exploit the property further. The 
claim was equipped with a twenty-stamp mill and cyanide plant, operated by water- 
power, an 80-horsc-power steam-engine being used, however, to supplement the Peltons 
in summer time. This company, when low-level developmental work proved unsatisfac- 
torj', disposed of the property to the syndicate, which in 1904 organized the Auckland 
Gold-mining Company. The latter continued operations for about four years. The 
returns recorded are as follows : 1900-4 (Mananu) — Tons crushed, 7,099 ; yield, 9,895 oz. ; 
value, £18,094. 1905-8 (Auckland)— Tons crushed, 2,774 ; yield, 5,992 oz. ; value, 
£10,131. Totals— Tons crushed, 9,783; viold, 15,087 oz.; value, £28,225. 

The rocks of the claim are all andesites or dacites, in various stages of alteration. 
RhyoUtes, however, occur to the north-westward within 60 chains of the workings, and to 
the south-eastward therefrom at a somewhat greater distance. It is not unlikely that 
the rock-alteration and vein-formation in the andesites followed the extrusion of these 
rhyolites, as the latter rocks carry the veins in the Wharekirauponga Valley to the 
south-eastward. One reef, together with the loop vein — the Ruanui^has been worked, 
the drifts extending in all over a stretch of 900 ft. The strike of the main reef is 
N. 20° E., and its dip is usually about 70° to the eastward. Four adits gave access to 
the workings — No. 1, with an average of 63 ft. below the outcrops ; and Nos. 2, 3, 
and 4, spaced at intervals of 65 ft., 70 ft., and 80 ft., respectively, giving a total vertical 
range of 268 ft. The reef, which throughout the workings varied considerably in width, 
averaged about 20 in. In the upper levels the veinstone was nearly all oxidized, and 
consisted of a friable rust-stained finely cr}'StaUine quartz, some of which showed a curly 
banded structure. Gold in a finely divided state was occasionally visible. Pyrite occurred 
only as sparsely distributed remnants, but became more prominent at lower horizons. 



96 

The best ore mined was derived from the block extending from No. 1 level to the 
surface, the longitudinal hmits of which (420 ft.) were determined by the surface-contours. 
This block included the Euanui loop vein. From No. 1 to No. 2 levels the ore showed 
a gradual impoverishment, and below the latter level the developmental work revealed 
very little veinstone that could be classed as ore. 

At Nos. 3 and 4 levels the vein fissure showed, on the whole, diminishing strength, 
and the vein-material included a good deal of silicified country rock and sUckensided 
puggy material. The wall-rock of the lower horizons, moreover, exhibits less advanced 
propyhtization than above, much of it consisting of a coarse-textured spotty bluish- 
grey chloritized andesite, with splashes of pyrite in the joint-planes. Near the vein-walls 
there is evidence of movement and crushing. From No. 4 level a small streak of ore 
is said to have been followed down in a winze for a few feet, but beyond this no 
further attempt has been made to prove the reef at a depth. 

The data which can be gathered from an examination of the old worldngs in their 
present state are somewhat meagre, but it would appear that the ore-shoot worked was 
in great part a product of superficial secondary enrichment. Ha\ang regard to this 
and to the character of the country rock at No. 4 level, the prospects of development at 
lower horizons appear indiflterent. No great amount of prospecting has been done apart 
from the work on the reef described. 

Glamorgan Claim (area, 100 acres ; owners, Glamorgan Gold-mining Company, 
Limited, Auckland). — The gromid held by the Glamorgan Company lies on both sides 
of Wentworth Stream, just above the mouth of the principal tributary, the Wairoa. 
The claim comprises the older holdings, known as the Goldwater, Silver King, and 
Herald, and the eastern portion of the Observer ground. 

The Goldwater vein is reported to have been discovered in 1887 by McWilhams 
and party, prospectors. Soon afterwards the Goldwater Company was formed to work 
the ground. Patches of rich argentiferous stone were mined, but no profits were made, 
and after a year or two exploration ceased. In 1897 an attempt was again made to 
work the claim by the Prince Charhe Gold-raining Corapany, but Math disappointing 
results. In 1909 the present company was organized to further exploit what were 
considered the most promising portions of the older claims. Altogether ore to the value 
of £1,375 is stated to have been obtained from the several portions of the Glamorgan 
Claim, mainly from the Goldwater reef. 

The country rock consists entirely of propyhtized andesite, considerably oxidized in 
all the surface workings. 

The area encloses many quartz veins, but most of them lack strength, and are not 
well defined. 

The veinstone of the principal reefs is usually of a whitish granular or saccharoidal 
nature, and contains in general very little pyrites. Platy quartz, pseudomorphous after 
calcite or some other rhorabohedral carbonate, occurs in places. The gold-silver content 
is confuied to veinlets and patches of dark-grejish coloured argentiferous sulphide (mostly 
argentite), the veinstone apart from this being practically valueless. 

The Goldwater reef, wliich outcrops on a ridge on the southern side of the Went- 
worth Stream, is 8 ft. or 9 ft. -nide at the surface, but in the several drives entering 
from the steep slopes descending to the creek-bed it is, on the whole, markedly len- 
ticular, and of less average width than that mentioned. At the surface some very rich 
stone was obtained. It is said that 3 cwt. of selected ore from a parcel of 11 tons was 
crushed at the Kuranui battery, Thames, for a return of £150. The shoot of ore located 
appears to be very short, both at the outcrop and in the prospecting-drives a httle dis- 
tance below. In the lowennost drive, about 20 ft. above the creek-bed, two reefs were 



97 

cut ; but both were here vahieless. If the poorly defined ore-shoot of the upper levels 
proves to have a southerly pitch, its projection to the low level would bring its position 
south of the point where the reef has been intersected. 

In the Silver King portion a 3 ft. reef has been exposed in surface workings. The 
character of the stone here is the same as that of the Goldwater. 

On the Herald portion a reef var3'ing from 2i ft. to 4 ft. wnde has been disclosed, and 
a winze is being sunk on it from the outcrop, while dri\'ing is in progress to cut it 
about 125 ft. lower down. The veinstone resembles that of the Goldwater, and carries 
on the hanging-wall side much manganese-dioxide. Argentite spots and veinlets are 
noticeable here and there in the quartz. 

The Glamorgan reefs carry in ])atches fairly good ore, but so far these patches 
have proved too small and scattered to mine at a profit. The ratio of silver to gold in 
the ores of this locality is high, as the assays of picked samples indicate, and metal- 
lurgical costs are consequently relatively high. (1.) Ore from Silver King section : Gold, 
6 dwt. 22 gr. per ton; silver, 149 oz. 19 dwt. 10 gr. per ton. (2.) Ore from Goldwater 
section: Gold, 1 oz. 10 dwt. 6 gr. per ton; silver, 141 oz. 10 dwt. 4 gr. per ton. 

Wharekirauponga. 

The auriferous belt on the valley of the Wliareldrauponga Stream is confined to an 
area of rugged countr)- which is probably less than 250 acres in extent. It lies on 
either side of the deep gorge which occurs in the main stream just below the junction 
of Edmonds Creek. 

Prospectors were operating in this valley in the early " niiu^ties," and had discovered 
several reefs, but it was not until the formation of the Royal Standard Gold-raining 
Company, London, in 1896 that any considerable amount of capital was expended. In 
the year named over two hundred men were employed. An expensive tramway about 
eight miles long was constnicted to the claim from tidal water on the Otahu Inlet. 
Many houses were built, and extensive excavations for a water-race and battery-sito 
were undertaken, but comparatively little crosscutting or drifting on reefs was done, 
although the property was but a prospecting proposition in its initial stage. In 1897 
the company, after having squandered many thousands of pounds, ahnost entirely above 
groujid, stopped practically ail work on the advice of its visiting engineer, and in 1899 
sold the property by auction. Subsequent owners carried out a little prospecting, and 
had 14^ tons of ore conveyed to Thames and treated at the School of Mines, for 
a return of £24 14s. lOd. After endeavouring in vain to raise capital for further 
exploration they abandoned the claim. 

The veins are apparently confined to intrusive banded rhyolites, which are here 
associated with rhyolitic breccias and tufTs overlying andesitic rocks of the " Second 
Period." The rhyoUtes are highly altered and silicified, especially in the proximity of 
the veins. The latter are numerous, varying in width from a line up to, say, 6 ft., 
whilst small ramifying stringers are everywhere conspicuous. 

The stronger veins nearly all strike in directions approximating north-south, and 
are generally vertical or dip westerly at high angles. The veinstone consists generally 
of fine-grained faintly banded quartz, in places rusty or stained with black oxide of 
manganese ; again, of rather a white milky colour. In these reefs gold-silver is either 
sparsely distributed or altogether wanting. In several reefs the veinstone differs con- 
siderably from that described. It consists mainly of siUcified and brecciated country, 
cemented by whitish chalcedonic quartz, and containing much soft white kaoUnic or 
puggy material. It is this type that carries the major gold-silver contents at Whare- 
kirauponga. 

7 — Waihi-Tairua. 



98 

Two reeLs in particular, enclosing veinstone of the second type described above, and 
occurring within 20 ft. of each other, have been explored. They cross the main stream 
just below the junction of Edmonds Creek, and vary from 3 ft. to 7 ft. in width. 
The gold or electrum exists in the vein-material in an extremely fine state of division, 
and, as seen in dish washing, is of a faint-yellow colour. Ore which proves on assay to 
be low grade gives, owing to the " flour}- " character of the electrum, a fair " tail " in 
the dish. A rather rough sampUng of these veins shows that in general the ore exposed 
is low grade, and would be unprofitable to work, even if a much greater tonnage of 
stone than that now available were to be obtained. The portion of the veinstone 
opened which gives the highest assays is confined to a length of about 120 ft., measured 
northward from the outcrop at the edge of the stream. Values, however, are not limited 
to this stretch, as the highest assay of all the samples taken — namely. 7 dwt. 13 gr. of 
gold and 16 dwt. 1 gr. of silver per ton — is referable to a sample collected from a drive 
on the south side of the river, about 100 ft. away from the outcrop on the north side. 

Apart from the further extension of the existing drifts on the veins in the hope of 
finding other ore-shoots, the claim is an expensive one to prospect. The obtaining of 
another 150 ft. of " backs " would entail over half a mile of crosscutting, mostly through 
hard sihcified rock. The alternative is shaft-sinking. The poor results as yet obtained 
at the existing adits, and the fact that the reefs are relatively small, give little 
encouragement for incurring any considerable expenditure. 

Extensive sinter-beds appear on the southern side of the Waiharakeke, and extend 
southwards into the Ramarama Stream. These sinters are of various colours and 
textures, and often contain pyrite, but their gold-silver content is negUgible. 

PuRiRi Valley. 

Mining has been carried on intermittently in the Puriri Valley since the opening 
of the Thames Goldfield in 1867. The area responsible for the greater part of the 
gold-}-ield is that including the Old Joker and neighbouring claims, in the lower part 
of the valley, which falls within the Thames Subdivasion, described in Bulletin No. 10. 

The Champion and Ready Bullion claims, situated near the smnmit of the main 
range drained by the headwaters of the Puriri, are so closely connected geographically 
and geologically with the Neavesville mines on the Tairua side of the range that 
they are considered with this latter group. In the remaining portion of the Puriri 
area there are no claims at present in existence. 

As the maps will show, both " First Period " andesites and dacites, as well as 
younger rhyohtic rocks, mostly tufaceous, have development in this area. Several 
narrow quartz veins were formerly worked by private individuals, and afforded rich, 
but very small, pockets of ore. These veins occur in the altered dacites and in small 
intrusive belts of rhyohte, but when followed in depth were invariably found to cut 
out or to become unprofitable. Recently the creek-beds have been thoroughly scoured 
and laid bare, owing to the " driving " of kauri timber by lumbermen ; and an exami- 
nation of the natural sections exposed confirms the verdict expressed by the miner — 
that the chances of permanent mining ever being estabUshed in this part of the valley 
are remote. 

A httle gold is being shed from local areas of sihcification in the rhyohtic tuffs, 
but such occurrences are of no commercial importance. 

Omahu Valley. 

Mining in Omahu Valley dates back to 1899. when good outcrop ore was discovered 
on the Sheet Anchor Claim by Tilsley Brothers. In addition to the Sheet Anchor, the 



99 

only claims which have contributed to the gold-output are the We Three and the 
Klondike. The total production of Omahu was valued at about £1,800- None of the 
properties ever paid for development. No mining is at present in progress. 

Sheet Anchor Claim (now abandoned). — This claim was situated on the low ridge 
separating the north branch of the Omahu from the valley of the Puriri, and was 
worked successively by the Sheet Anchor Gold-mining Company and the Omahu Mines 
(Limited). The production record is as follows : 1899-1903 — Tons crushed, 38 ; bullion, 
465 oz.; value, £3-17. 1905-8— Tons crushed,* 836; bullion. 945 oz. ; value. £741. 
Totals -Tons crushed, 874 ; bulhon, 1,410 oz.; value, £1,088. 

Equipment consisted in the earlier years of a light Tremain two-stamp mill. This 
was later replaced by a five-stamp mill and cyanide plant, connected with the mine by 
aerial tram. 

The rock forming the greater portion of the ridge which was the locus of the 
Sheet Anchor workings is andcsitic, but altered rhyolitic tufT constitutes the capping 
or superficial formation. Small intrusions of rhyolitic rock may also exist, as judged 
from the section exposed in the creek south of the workings. The workings themselves 
have collapsed, and scarcely any outcrops are visible. The reef, it is stated, measured 
from 3 ft. to 5 ft., was very flat-lying, and appeared to " roll " with the contour 
of the country. The greatest amount of overburden did not exceed 40 ft., and a lower- 
level adit driven about 1.000 ft. failed to intersect anything corresponding to the 
erratically disposed ore-body of the upper workings. A few small quartz veins were 
cut in this long adit, but these proved of little or no value. 

The ore-body consisted of milky-white finely granular quartz, with rust-stained vesi- 
cules and joint-planes, and showed occasional spots of silver-sulphide. The gold, even in 
the richest ore (£33 per ton), occurred in a very fine state of division. From descri])tions 
received, it seems that the vein occurred in the rhyohtic tuffs at or near their irregular 
contact with the older andesites, and that the chances of this rather superficial ore- 
sheet persisting into the underlying andesites are not promising. 

We Three Claim (now abandoned).- This claim was situated on the north side of 
the ridge separating the two main branches of the Omahu, and the workings are 
distant not more than 35 chains from those of the Sheet Anchor. It was worked 
by private individuals in 1903. when 2| tons of oxidized disjointed outcrop ore gave 
92 oz. 7dwt. of bullion, valued at £37 128. Id. From 1905 to 1907 the Omahu Mines 
(Limited) owned this ground in conjunction with that of the Sheet Anchor, and the 
ore from both claims was treated together (see Sheet Anchor returns). In 1908 the 
Last Shot Syndicate raised from the We Three reef 150 tons, which yielded £340 8s. 7d. 
Machinery for shaft-sinking was in course of erection when the project was abandoned. 
The plant, including the battery, has recently been removed. The country rock of 
the claim is entirely andesitic, that in the vicinity of the workings showing advanced 
alteration. It seems probable that mineraUzation was contemporaneous with that 
of the Sheet Anchor — that is, it followed the extrusion of the rhyolites. 

The only vein located in the workings strikes N. 20° E., and did not exceed from 
8 in. to 12 in. wide. The pay-ore was confined to the oxidized zone, and was much 
crushed and disjointed, partly re-cemented, and mixed with rusty clayey material. The 
tenor of the original veinstone appears to have been raised by superficial secondary 
enrichment. Some winzing was done from the adit level, and this proved the imoxidized 
veinstone to diminish both in width and value. 



* Probably portion of this was derived from the We Three Claim, which was also at this time the 
property of the Omahu Mines (Limited). 

7 * — Waihi-Tairua. 



100 

The Klondike Claim (abandoned). — The Klondike Claim was situated in the high 
country, about half a mile to the eastward of the Omahu Peak, and was worked 
intermittently from 1901 to 1904 by an Auckland syndicate. A small five-stamp mill 
was erected at the base of the high waterfall in Klondike Creek, and was connected by 
aerial and ground tram with the workings. The syndicate was ill advised in incurring the 
expenditure' on this plant. It was removed after 245 tons of ore had been crushed 
for 30 oz. lldwt. of bulhon. valued at £82 5s. 8d. 

The country rock consists of rhyohtic tuffs and intrusions of rhyolito and dacite 
of the " Third Period." Small erratic seams, along which sparse metalhzation has 
occurred, have been followed in several small adits, and from these workings the small 
amount of low-grade ore crushed was derived. 

Maratoto. 

The Maratoto mining district lies within the area drained by the Maratoto, 
Paiakarahi (Peel's), and Waipaheke creeks, three southern tributaries of the Hikutaia 
River. Communication is afforded by the graded road connecting Hikutaia \\ith 
Waitekauri, via the Maratoto Valley. From this a branch road connects with the 
claims in Peel's Creek, and a rough track with those in Waipaheke Valley. 

The history of mining in Maratoto since the first discovery by McBrinn in 1887 has 
been briefly narrated (see pages 13-14). The value of the gold-silver output has not 
been accurately recorded, as much of the richer ore, which was highly argentiferous, 
was exported for treatment. The production totals about £25,900. With the exception 
of the profits wliich may have been derived by individual prospectors from the sale 
of parcels of rich ore from shallow adits, mining in Maratoto has afforded no profits to 
anv of the companies that have operated. 

The vein-bearing rocks are the altered andesites and dacite's of the " First Period." 
These are, as the maps will show, flanked or overlain by andesitic rocks of the 
" Second Period," and in places have been broken through by the still vounger 
rhyolites. All the sharp peaks of bizarre form, which here constitute a conspicuous 
feature of the landscape, are plugs or dissected sheets of massive rhyohte. No quartz 
veins have been found in the rhyohtic rocks, or even in the " Second Period " volcanics. 
The formation of the veins was probably coeval with that of the Martha veins at 
Waihi — namely, it preceded the two later periods of volcanic activity. 

The following mining properties enclose all the veins which call for special remark : 
Walker's Maratoto, Maratoto ConsoUdated, Silverstream, and Tellurides Proprietary. 

Walker's Maratoto (area, 80 acres 2 roods 2 perches ; owners, private individuals). — 

Walker's Maratoto is the claim upon which the earliest discovery of ore in the district 

was made. It is located in the hilly country lying between Maratoto Stream and 

its western tributary, McBrinn's Creek. The production figures are as follows : — 

-, /-A Tons 

Year. Company. ^^^^j^^^j_ 

1888-95 .. Maratoto .. .. 1,378* 

1896-1900 .. „ .. .. 640 

1904-7 .. New Maratoto .. 1.054 

1910 . . Prospectorsf 



BuUion. 

Oz. 
11,596* 


Value. 

£ 
5,800 


3,995 


1,205 


3,384 


955 


6 


4 



Totals .. .. 3,072 18,981 7,964 



* Approximate. 

t In a description appearing in Mines Report, C.-3, 1899, it is stated that " in about eighteen months 
£12,000 worth of bullion was extracted," but records do not confirm this statement. 



101 

The claim has been worked altogether from adits, the lowest of these having an 
elevation of some 350 ft. above Maratoto Stream (McBrinn's Creek junction). The 
richer ore of the earher days was exported. The first process adopted on the claim 
was pan amalgamation ; but in 1900 and subsequent years the cyanide process was 
employed. It is certain that the treatment of this highly argentiferous ore was at all 
times unsatisfactory. 

The vein-bearing country consists of greenish-grey andesitic and dacitic rocks — lavas 
and well-consolidated breccias in various stages of alteration. In the most advanced 
phase of alteration the rocks assume a bluish-white colour, and contain pyrite. 

Two reefs were worked — the Maratoto and the Pay Rock. These were approxi- 
mately parallel, strike about N. 20° E., and dip to the westward at high angles. 
The Maratoto is a strong reef, and within and beyond the limits of this claim it has 
been worked at various points over a length of 7,300 ft. Furthermore, outcrops of quartz 
along its general line of strike suggest that it has considerably greater extension. 
This reef ranges up to 25 ft. wide, and is said to average about 6 ft. throughout the 
Walker's Maratoto workings. The Pay Rock reef, wliich also shows considerable persist- 
ence, ranges in general from 2 ft. to 4 ft. in width, and has been drifted upon in 
this claim for over 500 ft. 

The veinstone of both these reefs — and, in fact, of the other Maratoto lodes — differs 
but httle from that of Golden Cross and Komata. It is, in the main, a quartzose 
replacement after a mangaiiiferous calcite, with ribs and bunches of massive quartz 
evidently deposited in fissures and open cavities. Calcite itself was, from all accounts, 
absent or inconspicuous at the upper levels. It constitutes the predominant and, in 
places, the exclusive vein-filHng at the lower levels. Most of the ore mined was derived 
from the surface levels, and was confined to small pockets and lenticular bands. One 
stretch, however, of about 150 ft. of the Maratoto reef was reported to carry fairly 
good ore throughout. These levels in the vicinity of the stoped blocks are not now 
accessible. The low level revealed no ore worth mining in either reef, although very 
small bunches carrying sulphides are occasionally visible in massive quartz near the 
actual walls of the veins. 

Argentite was the dominant ore-mineral, and with it was probably associated a little 
hessite. Available figures show that the bulhon extracted by plate amalgamation was sold 
for 128. 2d. per ounce; that by subsequent cyanidation, at 2s. lid. per ounce. The 
Maratoto ore is therefore considerably higher in silver than that of the Golden Cross 
and Komata areas. 

Maratoto Consolidated (area, 96 acres 2 roods ; owners, private individuals). — The 
Maratoto ConsoUdated Claim Ues south-westward of Walker's Maratoto, and mainly within 
the valley of Paiakarahi (Peel's) Creek. It constitutes part of an area of 350 acres 
owned and worked from 1896 to 1903 by the Hikutaia Gold Syndicate, of London. 
This syndicate was organized to determine, by systematic developmental work and 
the treatment (cyanidation) of bulk parcels of the ore, whether the proposition was a 
payable one. Ore to the amomit of 7,409 tons was mined and treated, and this 
yielded 2,512 oz. of bulhon, valued at £5,251. The management thereupon concluded 
that the ore was too low grade to warrant the expenditure of further capital. 

The country rock is similar to that in the Walker's Maratoto Claim, and the 
same two reefs — the Maratoto and the Pay Rock, in addition to another vein called the 
Liverpool — have been worked. Seven adits were driven at various altitudes from points 
on either side of the valley. The greatest depth of the workings below the surface 
was 425 ft. 



102 

The Maratoto is the reef upon which most of the work was done. It was followed for 
over 1,600 ft., and is reported to have averaged 10 ft. in width throughout the whole 
of the workings. The veinstone, which is practically all oxidized, consists of quartzose 
replacements after calcite and bands of finely crystalhne massive quartz, with, in 
places, considerable admixture of sheeted minerahzed country rock. The white quartz 
is, in general, stained with iron and manganese oxide, and the greater part of it is 
crushed, friable, and easil}' mined. Calcite is absent or inconspicuous in the veinstone 
of the horizons exploited ; but it may reasonably be considered to exist not far below the 
creek-level. As the production figures will indicate, the proportion of gold to silver is 
much higher here than at Walker's Maratoto, the value of the bullion averaging nearly 
£2 2s. per ounce. 

The other reefs carry similar veinstone, but are smaller, and have been exploited 
over a much less longitudinal extent. 

The exploratory work of the Hikutaia Gold Syndicate has at least served to prove 
the existence at adit levels of a large tonnage of easily mined low-grade ore, which 
may possibly yet be worked at a profit. Regarding deeper-level workings, however, the 
following statement appears in the Mines Report* : " So far it has been possible to open 
up the mine with adit levels ; but for deeper levels it is questionable if adits would 
be profitable, owing to the great length of drivage necessary to cut the reef." The 
hkeUhood of the primary barren calcitic matrix existing at horizons bclov,- those exploited 
must also be taken into account. 

Silverstrcam Claim (area, 100 acres ; owners, the Silverstream Gold-mining Company, 
Auckland). — The Silverstream Claim is situated at the jmiction of the two main head- 
water branches of Maratoto Stream, and about 50 chains, as the crow flies, from the 
Maratoto-Waitekauri Saddle. Older claims lying partly or altogether within its boundaries 
are the Retreat. Ravenswood, Silver Queen, and Camoola. Mining has been carried on 
in a rather desultory fashion on some of these claims for over twenty years. 

It is stated that ore to the value of over £5,000 has been taken from, the Silver- 
stream reefs, but the only available records refer to the years 1904-7, during which small 
parcels aggregating 35 tons were exported, for returns totalling £1,668. 

The vein-bearing rock-complex consists of the "First Period" andesitic and dacitic 
lavas and breccias common to the Maratoto - Golden Cross belt. In the Silverstream 
low-level adit the beds have a general dip to the south-east. 

The veins upon which work has been done number four. These present in strike 
a general parallelism, and, in order from north to south, arc known respectively as 
Corbett's. Julia, Silver Queen, and Camoola. The adit- workings on all these are on the 
eastern side of Maratoto Stream, but there are also some old adit-workings on the 
Camoola, in the valley of the western headwater branch. 

Corbett's Reef : Strike, about N. 20° E. : dip, westward at high angles ; average 
width, 4 ft. This reef has been drifted on about 250 ft. from the level of the main 
creek. The veinstone consists, in the main, of cavernous quartzose replacements after 
calcite with minor ribs of massive quartz, the whole stained rusty brown and black 
with iron and manganese oxides. Sparsely distributed small bunches of the massive 
quartz show a httle argentiferous sulphide. No pay-ore has been obtained. The 
average assay value of the veinstone is said to be about 10s. per ton. A picked 
sample from the sulphide bunches assayed — Gold, 22 gr. per ton ; silver, 31 oz. 15 dwt. 
12 gr. per ton. 

The Juha Reef: Strike, N. 27° E. ; dip, about vertical; width, 18 in. and under. 
This vein, which Hes a few chains east of Corbett's, afforded from shallow adit-workings 
the greater part of the rich argentiferous ore exported from the claim. The veinstone 

* C.-3, 1899. 



103 

which occurs as lenticular masses alonp the fissure, consists mainly of hard white 
crystalline quartz of a granular type. Evidences of pseudomorphism after calcite are 
here much less evident than in the case of the other reefs. Certain lenses of the 
veinstone carry argentite, and with this mineral is associated hessite (the telluride of 
silver) and a httle gold. The following assays* of picked ore from this and the Silver 
Queen reef are of interest: No. 1 — 13dwt. 1 gr. of gold, and 436 oz. 8dwt. 12 gr. of 
silver per ton; No. 2 — 6dwt. 12 gr. of gold, and 391 oz. 13dwt. 11 gr. of silver per 
ton; No. 3 — 4d\\i:. 1 gr. of gold, and 218 oz. ISdwt. 12 gr. of silver per ton. These 
samples contained the following percentages of tellurium : No. 1, 0-38 ; No. 2, 0-23 ; 
No. 3, 016. Copper, which in this district appears to be a fair" indicator" for good ore, 
was present to the extent of 0-20 per cent., 0-30 per cent., and 0-16 per cent., respectively. 

Ore is said to have been stoped here and there over a length of 150 ft. The 
present company is driving, from the lowest level practicable, an adit which wtH give 
70 ft. of " backs " under the older workings. 

The Silver Queen Reef: Strike, appro.ximating N. 30° E. ; dip, vertical or westward 
at high angles; width, about 3 ft. 6 in.; distance east of Julia. 180 ft. This vein has 
been prospected in two small adits ovi>r a strike of from 200 ft. to 300 ft. By far 
the greater part of the veinstone is similar to that of Corbett's reef, and the gold- 
silver values are negligible. Bands and bunches of the hard white crystaUine quartz, 
as in the Julia reef, however, occur here and there. The largest of these bands exposed 
is about Sin. wide, and forms for a short distance the hanging-wall portion of the vein. 
Silver-bearing ore (containing argentite and hessite) is stated to have been mined from 
various patches over a horizontal length of 80 ft. A stretch of about 25 ft. in the lower 
of the two adits reveals the best ore. An extension of the low-level adit now being 
projected to cut the JuUa reef will afford about 160ft. of "backs" below the present 
workings. 

The Camoola Reef : Strike. N. 15° E. ; dip, westward at high angles ; width, about 
20 ft.; distance east of Silverstream vein, say. 16 chains. The Camoola is perhaps a 
stronger vein than the main Maratoto reef, but, unfortunately, has yielded no ore. 
That it carries gold in places is evident by the "prospect" that can be obtained in 
debris of the creeks which receive its shoadings. The veinstone where exposed consists 
almost entirely of cavernous quartzosc replacements after calcite, with bands of massive 
quartz and sheets of silicified propylite, the whole stained rusty brown and black 
with iron and manganese oxides. 

The workings appear to be confined to two localities. The vein has been intersected 
in a crosscut just below the Maratoto Waitokauri Road, and again about 26 chains to 
the south-west, in the valley of Camoola Creek. In the latter workings it has been 
drifted on for 350 ft. Assays of general samples taken by the writers afforded : No. I — 
Gold, trace; silver, lldwt. 5 gr. No. 2 — Gold, 6 gr. ; silver, 2 oz. 15dwt. 8 gr. 

Tellurides Profrietary Claims (area, 550 acres 2 roods 6 perches ; owners, the 
Tellurides Proprietary. Limited, Auckland). — A large area of ground, comprising the 
Gordon, Gordon Extended, Dreadnought, Excellent, Irving, Privateer, and Volimteer 
claims, has recently been taken up by the company named. 

The principal underground work is confined to drifting on the Welcome Jack reef 
in the Gordon Claim, which adjoins the Silverstream Claim. This vein, which varies 
from 4 ft. to 12 ft. in width, strikes about N. 65° E., and, on the whole, dips to the 
north-west. The veinstone is identical with that of Corbett's reef in the Silverstream, 
and has afforded no ore. Sporadic bunches carrying silver-sulphides — and probably the 
telluride, hessite — are occasioDally seen. 



* Supplied by A. T. Firth, Auckland. 



104 

From an extension of the drift on the Weleonie Jack reef it is proposed to project 
a crosscut to intersect reefs which are expected to persist north-east from the Silver- 
stream property. 

On the Volunteer Chiim prospecting-work has mainly been confined to a reef about 
3 ft. wide which occurs above the waterfall on Volunteer Creek, a mile above its 
junction \\ith the northerly branch of Waipaheke Stream. This reef, which strikes 
N. 60° E., and dips about 55" towards the south-west, carries pyritous white quartz, 
but has so far yielded no ore. The reef is traceable further southward, but is here 
weaker, and all work on it has proved unprofitable. 

PeeVs Creek Prospects. — In addition to the veins of the Maratoto Consolidated, in 
Peel's Creek Valley, several quartz reefs and quartzose formations are kuowai to occur. 
A narrow quartz vein in a zone of highly pyritous dacite occurs just above the mouth 
of Arizona Creek. Similarly, stringers of quartz intersecting highly altered rocks have a 
wide distribution at the head of Alpine Creek, and a large quartzose formation occurs 
in Incognito Creek. 

On the Incognito Creek formation prospecting-work has been done. Two drives 
have been put in just above the level of the creek-bed, and several at higher elevations 
further to the north-eastward. In one of the lower drives a quartzose formation was 
penetrated for 10 ft., and in the other drive for 27 ft., but, as the strike of the formation 
in neither case has been detemiined, correlation is impossible, and the actual widths are 
unknown. The material consists, for the most part, of mineraUzed brecciated coimtry, 
highly pyritous, and enclosing ramifying stringers of white quartz. Platy quartz, 
pseudomoi-phous after calcite, is also common, and small patches of chalcopyrite occur 
with pyrite in the unoxidized quartz. All of the veinstone in the upper workings is 
oxidized. Parcels of ore are sa'd to have been mined from this formation, but assays 
made from samples collected by the writers indicate only a low gold-silver content. 

Waitekauri Extended Claim (abandoned). — The Waitekauri Extended Claim, better 
known as the St. Hippo, was situated on the Waitekauri-Maratoto Saddle, and adjoined 
the northern boimdary of the Golden Cross Claim. 

From the year 1895 to 1901 this ground was owned and worked by the Waitekauri 
Extended Gold-mining Company, of London, but proved unprofitable. In all, 6,017 tons 
of ore was treated, for 6,044 oz. of bulLon, valued at £6,149 9s. 7d. In 1901 the 
property was acquired by the Waitekauri Gold-mining Company, the proprietors of the 
adjoining Golden Cross iMine, but was abandoned by them in 1904, the hmited prospecting 
operations undertaken having disclosed no profitable ore. All the workings are now 
inaccessible. 

The claim was worked by adits opening from the Maratoto slope of the range, the 
lowest of these adits (No. 3) intersecting the main reef about 400 ft. below its outcrop. 
An aerial tram a mile and a quarter long connected this adit wdth a forty-stamp mill 
and cyanide plant erected in Maratoto Creek. 

Several reefs were cut in prospecting-crosscuts, but mining was confined to one 
large reef, which would average 35 ft. in width. This reef, which strikes N. 18° E., and 
dips to the eastward at high angles, is approximately parallel to the main Golden Cross 
lode, and is distant therefrom about 30 chains. The enclosing cotmtry rock is a propyUtized 
andesite or dacite, similar to that predominating throughout the Golden Cross - Maratoto 
belt. 

The reef has been drifted upon at the lowest adit for 1,030 ft., 450 ft. north and 
580 ft. south of the main crosscut. At a point about 325 ft. north of the crosscut the 
plans show the reef to be displaced about 3 ft., the direction of the throw indicating the 
existence of a reversed fault. The stope-length of the block from which the ore treated 



3i cLccompany BuUeUn N" IS.Wathj-Tairuay SuhaUytsrorv.Hctzj^akiBivisioTV, Audtlarul LanA Dtstrtct 




By Authority: John Mackay, Government Printer. 



106 

was obtainod is short — about 120 ft. — and tho pitch of the shoot is about vertical. The 
veinstone on the dumps is evidently in part a quartzose replacement after calcite. It 
is also significant that a calcite vein measuring 20 ft. in width, and striking approxi- 
mately parallel to the reef, was intersected in the main crosscut about 'ISO ft. from the 
foot-wall or western side of the reef. A shaft in process of being sunk from the No. 3 
level drift had attained a depth of 76 ft. when the Waitekauri Extended Company 
abandoned operations. 

Having regard to the record of the adit-level operations, and mure particularly to 
the genesis of the veinstone, abandonment was evidently justified. 

KOMATA DlSTRKT. 

The Komata Goldfield occupies the upper part of the valley of Komata Stream, and 
extends eastward therefrom over the high bush-dad iiills wliich intervene between 
Komata and Waitekauri. As in most of the other mining camps of Hauraki, the 
proven auriferous area at Komata is not extensive, being confined to the watershed of 
the southern and central headwater branches of the main stream. Within these 
limitations a httle alluvial gold can be obtained from the debris of almost all the 
creeks. 

As the historical section of tliis report will show, mining at Komata dates from the 
year 1891, and the total value of the gold-silver production to the close of the year 
1910 is £402,394. 

The area is one of decided relief, being deeply dissected by numerous small streams. 
These descend rapidly from relatively high altitudes to the level of the open valley of 
the Komata at and below the junction of the three headwater branches, where the small 
township and the battery are situated. Komata is connected with the Thames-Paeroa 
railway-line by a good metalled road, which follows the valley of Komata Stream. 
From this road a well-graded track leads over the range, past the various workings of 
the Komata Reefs Mine, to the settlement of Waitekauri. 

The geological conditions in this area bear a striking resemblance to those existing 
at Maratoto and Upper Waitekauri. The vein-bearing rocks consist of "" First Period " 
dacitic lavas and, occasionally, breccias exhibiting various stages of alteration. This 
older volcanic complex is overlain in the lower part of the valley by the non-vein- 
bearing Beesou's Island Series. Some belts of black gla.ssy andesite occurring \vithiii the 
area of " First Period " volcanics are probably intrusives, referable to this later period. 

The principal quartz reefs have a general strike of N. 40° E., and with them 
occur several iinking-veins and branch veins, wliile smaller stringers of quartz are 
common throughout the whole propyHtized rock-complex. The vein-material, as the 
following description of the Komata Reefs Claim will show, consists largely of a quartzose 
replacement after calcite. and in this respect resembles the vein-material of the Maratoto, 
Golden Cross, and Waihi goldfields. 

The Komata Reefs Mine (area, 340 acres and 4 perches ; owners the Komata 
Reefs Gold-mining Company, Limited, London ; capital. £2(JO,000, divided into 800,000 
shares at 53.). — The Komata Reefs Mine is the only property now ixing worked in 
Komata. It comprises five claims, amongst which are included Komata Reefs, Te-ao- 
niarama, and Burbank. The metal-output of the area constituting these claims is as 
follows: Komata Gold-mining Company (Auckland), 1892-96 — Tons crushed, 6,487; 
value, £33,377. Komata Reefs Gold-mining Company (Limited). (London), 1897-1910 — 
Tons crushed, 181,229 ; value, £369,017. Totals— Tons crushed, 187,716 ; value. £402,394. 
Any profits made by the Komata Company are not recorded. Dividend-payments of 
the Komata Reefs Gold-mining Company (Limited) total £33,333. 



106 

The configuration of the country has permitted all mining up to the present being 
done from adit levels. The lowest level (No. 8) was opened at an elevation of 614 ft., 
and is situated a few chains above the junction of the southern branch with the main 
Komata Stream. Below this adit-entrance, it may be stated, the gradient of the stream- 
bed is relatively low. Above No. 8 level, adits have been opened at the folloAving 
elevations : No. 7, 100 ft. ; No. 6, 186 ft. ; No. 5, 284 ft. ; No. 4, 404 ft. ; and a shaft, 
having a collar-elevation of 780 ft. above this datum, has been sunk. Between No. 4 
level and the shaft-collar are small adits, for the most part not used, known as No. 3, 
No. 2 (Smithy level), and No. 1 (Hopper level). The shaft, which is vertical, is con- 
nected with all workings between the Smithy level and No. 8 level. 

The battery, connected with No. 8 level by a horse-tram about a mile in length, is 
a well-equipped Httle plant operated by water-power. It consists of two Blake crushers. 
Challenge ore-feeders, twenty stamps (1,1001b. each), two tube mills, elevating-wheels, 
separating-boxes, amalgamating-plates, cyaniding - sand vats. Dorr shme-thickener, ten 
Brown and McMicken sUme-agitators, Moore vacuum filters, extractor-towers, and all 
appurtenances. Amalgamation is practised, and 46-6 per cent, of the gold-silver is 
recovered on the plates. The extraction from all processes is said to total 96-6 per cent, 
of the assay value of the ore. 

Almost the whole of the pay-ore mined has been derived from two veins, known 
respectively as the No. 1 reef and the No. 2 reef. Hartridge's " leader " and Lavington's 
reef have also jnelded ore. The No. 1 and No. 2 reefs exhibit a general parallelism, with 
an average strike of a few degrees east of north. At the surface they were about 140 ft. 
apart, but in the lowest workings they are separated by only some 30 ft. or 40 ft. of country. 

The No. 1 and No. 2 veins are markedly lenticular, both in longitudinal and vertical 
extension, and are enclosed between indefinite and irregular walls. In the northern end 
of the workings the vein fissures evidently weaken, and both veins spUt into a number 
of stringers. The wall-rocks are for the most part hard propylite, in places more or 
less siUcified. Again, softer propyUte occurs, and occasionally darker and somewhat less- 
altered dacite. The width of the veins varies greatly. The profitable ore usually occurs 
where the fissures widen in hard propylite, and where, consequently, the width of vein- 
stone is considerable. Thus, in most of the non-payable portions of the No. 1 and No. 2 
lodes in Komata Reefs, or southern section of the property, at No. 4 level, their width 
rarely exceeds 3 ft. In the profitable portions of both veins in the Te-ao-marama or 
northern section the width of veinstone would average, above No. 4 level, about 10 ft., 
with local bulges up to, say, 20 ft. Below No. 4 level, here the width is generally less. In 
the softer propyhte the fissures are, as a nile, narrower than in the hard firm propyhte. 

The unprofitable veinstone consists essentially of calcite, finely crystalhne quartz, 
lamellar quartz often rusty or stained with black oxides of manganese. Pyrite occurs 
only very sparsely in the unoxidized ore. Much of the calcite or carbonate evidently 
contains some manganese, as judged by the quantities of manganese - oxide associated 
with the oxidized pseudomorphous quartz. Some of it, however, is almost pure calcite. 
as the following analysis* of a sample from one of the stopes indicates :• — 

Per Cent. 
Lime (CaO) . . . . . . . . . . . . 55.56 

Sihca (SiOa) .. .. .. .. .. .. 00-73 

Water driven off (100°) . . . . . . . . . . 00-04 

Carbon-dioxide (CO 2) .. .. .. .. .. 43-67 

100-00 
Specific gravity of specimen, 2-67. No trace of manganese w^s present. 

* By R. J. Morgan. 



107 

The profitable veinstone consists essentially of a breccia of country rock cemented 
by quartz and calcite. In many places calcite is undoubtedly the oldest mineral present. 
Again, calcite occurs which is certainly younger than some of the quartz. The quartz 
is more or less pyritous, and, where oxidation has taken place, rusty. It is frequently 
of the pecuUpr white ilinty "alabaster" variety. A noteworthy fact is that the vein- 
stone of highe.°t value usually exhibits a faint banding. This banded quartzose — and, 
in places, partly calcitic — veinstone encloses films of argentite. Free olectrum is occa- 
sionally visible even in the unoxidized ore at present being mined. The included wall- 
rock breccia may be lughly mineralized, or, again, but little different from the normal 
propyUte. The former usually constitutes ore, while the latter is rejected. These 
breccia fragments varv in size from a fraction of an inch up to several feet, the large 
blocks being usually intersected by veinlets of quartz and calcite, extending from the 
main mass of the fissure-filling. 

Three main shoots of ore have been located. Two of these lie within the northern 
or Te-ao-inarama portion of the property — namely, one on the No. 1 reef and the other 
on the No. 2 reef^thc shoots being chsposed practically " back to back " in these 
parallel veins. The third slioot occurred within the southern or Komata Reefs portion 
of the mine and in the No. 1 reef. Hartridge's "leader" and Lavington's reef, branches 
of the No. 1, also contributed to the ore-output from this particular locahty. No. 2 reef 
in this portion, however, yielded no ore. A long stretch of barren or unprofitable vein- 
stone separated the ore-shoots of Te-ao-marama portion from the shoot of the Komata 
Reefs portion of the mine. 

The Te-ao-marama ore-shoots showed, on the whole, a steep pitch to the southward, 
and persisted through a vertical range of about 700 ft. Their greatest longitudinal 
dimensions were found to occur at No. 4 level (about 500 ft. below the outcrops). The 
shoot on No. 1 reef had here a length of 300 ft., and that on No. 2 reef 700 ft., 
although within these limits barren or unprofitable patches existed. Exact information 
regarding the dimensions and content of these shoots above this horizon is difiicult to 
obtain. Both reefs, however, are said to have afforded some rich outcrop ore, and from 
the outcrops to No. 4 level the greater part of the ore mined has been derived. From 
No. 4 level downward to No. 5 the strength and value of the shoots were fairly well 
maintained, but below No. 5 the slioot gradually shortens, and the ore tenor, on the 
whole, dinunishes. At No. 7 level the No. 1 reef shoot does not exist, and the No. 2 
reef shoot is of small extent. At No. 8 level, KXJ ft. lower down, neither reef has afforded 
ore, although in places bunches too small to mine at a profit were found. Stretches of 
both reefs at this level show only disconiierted lenses of calcite and quartz. Winzing 
below No. 8 level has revealed only barren veinstone, consisting almost entirely of calcite. 

The shoot of the Komata Reefs (southern portion), now abandoned, afforded all the ore 
mined by the company prior to 1900. The output to the end of that year amounted 
in value to about £36,000. This shoot on No. 1 reef persisted from the surface to 
about No. 7 level. The richest ore is said to have occurred in this lode where a strong 
reef (Lavington's) junctioned with it. Lavington's reef itself, except in the vicinity of 
this jmiction, yielded no ore. Hartridge's " leader " contributed some profitable vein- 
stone ; and it is noteworthy that the rich ore gave out in stoping before the surface 
was reached. No. 8 level revealed little or no ore in this portion of the property, and 
further prospecting by winzing was not attempted, owing to the volume of water to be 
encoimtered. 

In mining the various ore-shoots at Komata a considerable amount of hand-picking 
in the stopes has been practised. Low-grade or barren veinstone and unmineralized 
rock breccia occurs as patches almost everywhere, and is even associated with the higher- 
grade ore. This worthless material is picked out as far as possible, and used as stope- 



108 

filling. Much of the calcitic ganguc, however, which is almost barren, is too intimately 
associated with the quartz to admit of rejection. The estimation of the ore-reserve, 
owing to the varying proportion of the " rejects," is rendered difficult. 

At present the company is stoping on No. 1 and No. 2 reefs, Te-ao-marama Claim, 
between the Nos. 4 and 6 levels. On the average, seventy men are employed, and about 
850 tons of ore, returning about £1 17s. lOd. per ton, is being raised per month. The 
estimated ore-reserve at the close of 1910 totalled 13,700 short tons. The prospects of 
development-work below the No. 8 level proving profitable are, in the writers' opinion, 
remote. Above No. 8 level the possibihty of encomitering further ore-shoots on No. 1 
and No. 2 reefs, by drifting north-eastward, is discoimted by the pronoimced weakening 
of the fissures, which seems evident in this direction. A prospecting chance would be 
afforded by crosscutting either south-east or north-west from No. 1 and No. 2 reefs, at 
the horizon where the shoot of the Te-ao-marama Claim is widest and longest — that is, 
at the No. 4 level. Several parallel reefs, including Lavington's, Hartridge's, and others, 
are known to exist further south in the Komata Reefs portion of the property, and it 
is thought that if these reefs persist northwards they may carry ore-shoots in positions 
corresponding to the Te-ao-marama shoots of Nos. 1 and 2 reefs. 

Waitekauri Valley. 

Waitekauri, as the historical section will show (see page 8), was under examination 
by the prospector even prior to 1870, and includes the oldest mining district of the 
subdivision. The total value of the metal produced is approximately £500,000 sterhng. 

The various mines and prospects worked are scattered throughout the whole stretch 
of hilly country lying on the western side of the main Waitekauri Stream. This extends 
for a distance of four miles and a half from the Maugakara tributary (which may be 
taken as the northern hmits of the Owharoa area), northward to the Golden Cross- 
Maratoto Saddle, which overlooks the actual headwaters of the Waitekauri. 

The rocks of the whole of this belt are " First Period " volcanics — andesites and 
dacites — which have extension into the Komata and Maratoto watersheds. The volcanics 
forming the country on the eastern side of the Waitekauri Valley are the " Second Period " 
andesites and dacites, and, as recognized even by the earher prospectors, are non-auriferous. 

The mining claims, existing or abandoned, which call for description are the Golden 
Cross, Grace DarUng, Durbar, Huanui, old Waitekauri, Jubilee, Scotia, and Maoriland. 

Golden Cross Claim (area, 192 acres 3 roods 8 perches ; owners, the New Golden 
Cross Gold-mining Company, Auckland). — The Golden Cross Claim is situated in the 
upper part of the Waitekauri Valley, the principal workings being only 45 chains 
from the saddle on the water-pai-ting between tliis stream and the Maratoto branch 
of the Hikutaia Stream. A road for wheel traffic leads from the railway-station at 
Waikino up to the mine and across the saddle to Maratoto and Hikutaia. 

The Golden Cross reef was discovered by Lowrie Brothers in 1892. The prospectors' 
claim was purchased by Mr. T. H. Russell, who organized a small company to prove 
it. In 1895 the property, together with a large area of surromiding coimtry, was 
acquired by the Waitekauri Gold-mining Company (Limited), London. The mine" 
was connected by tram with a forty-stamp mill and cyanide plant situated in Waitekami 
Township, some three miles and a quarter down the valley. It proved a profit- 
making concern for about seven years, but was abandoned in 1904 as the result of the 
ore-shoot cutting out in depth. The present company acquired the property late 
in 1906, and has confined its operations to the adit levels, where blocks of low-grade 
ore, regarded as profitable, exist. A ten-stamp mill, to be worked by water-power, is 
being erected within 40 chains of the mine-workings. 



109 



The production record of the claim is as follows 



Year ending. 


Owners. 


Crushed. 


Value. 






Tons. 


£ 


Mar., 1893 ... 


Lowrie Brothers ... 


7 


260 


„ 1894 ... 


Golden Cross Company, Auckland 


600 


4,000'= 


„ 1895 ... 


Golden Cross Company, Auckland (Waitekauri 
Gold-miniu'^ Company) 


1,769 


7,114 


„ 1896 ... 


Waitekauri Gold-mininc; Company ... 


2,656 


9,860 


„ 1897 ... 


London 


11,410 


32,645 


„ 1898 .. 


»/ . . . 


23,383 


55,258 


„ 1899 ... 


,. It • • • 


22,840 


66,585 


„ 1900 ... 


n ti • " 


27,402 


80,469 


Dec, 1900+ .. 


II ,. . . . 


19,813 


49,837 


„ 1901 ... 


.... 


24,629 


42,558 


„ 1902 ... 


If II * . . 


14,801 


23,406 


„ 1908 ... 


New Golden Cross Gold-mining Company, 
Auckland 


246 


450 


„ 1909 ... 


Ditto 


105 


637 




149,661 


£373,079 




* Approximate. t Nine months. 







The Waitekauri Gold-mining Company, London, paid from the Golden Cross Mine 
dividends amoimting to £84,035. 

The country which encloses the workings presents but little local rehef, although 
the lowest adits have an elevation of 92U ft. above sea-level. The vein crosses the 
bed of the main creek which here incises country rising with easy slopes for some 
considerable distance along the strike of the vein. The " backs " available from 
the adit levels only ranged from 35 ft. to 25U ft. To obtain a further 300 ft. an adit 
was commenced down the valley just above the junction of Donnelly's Creek, but 
this was abandoned. 

The main adits — the Battery and the Kiln, which are on approximately the same 
level — traverse the reef, which strikes north-east, for a distance of 2,340 ft. From this 
horizon the "backs" on the reef for the extent of the ore-shoot averaged 200ft. 
Corbett's level was driven as an intermediate to facilitate the working of this block. 
Two shafts, 1,030 ft. apart, were sunk in the hanging-wall country on the strike of the 
lode. The No. 1, or .south-eastern, shaft was sunk from the surface to a depth of 
710 ft., or 58U ft. below the adit, and levels were opened at the following depths 
(below the collar): No. 2. 230ft.; No. 3, 330ft.; No. 4, 400ft.; No. 5, 500ft.; No. 7, 
700 ft.* The No. 2, or north-western, shaft was sunk 365 ft. from the collar or 280 ft. 
below the adit, and a level corresponding to the No. 2 already mentioned was opened. 
Pumping and winding machinery was erected on these shafts. This machinery was 
removed when the Waitekauri Company abandoned operations, so that, with the exception 
of the recently repaired portion of the adit levels, the workings are now inaccessible. 

The vein-bearing rocks of the Golden Cross Mine as far as can be ascertained 
from the shaft dumps, are pyroxene dacites containing a httle hornblende. In general 
appearance the less-propylitizcd rock is compact, greenish-grey, and porphyritic, with 
white feldspars, greenish ferro-magnesian minerals, and scattered pyrite. Breccias 
of similar mineralogical character are also present. Darker basalt-like varieties are 
noticeable here and there, and evidently represent " hard bars " or remnants of fresher 
dacite. The more highly propyhtized rock is, as usual, hght-coloured, highly pyritous, 
and not very hard. 



* The No. 1 adit level meets the shaft at 130 ft. below the collar. 



110 

Several reefs presenting a general parallelism in strike and dip, and exhibiting 
similar structural and mineralogical characteristics, have been located in this claim. Of 
these, only the Golden Cross or No. 1 reef (with its hanging-wall branch, the Southern 
Cross), has yielded payable ore. Two other reefs — the Empire and the Realm, both 
lying to the northward of the No. 1 — were intersected and drifted on in the adit 
level, but afforded no encouraging results. 

No. 1 reef, which, as already stated, has been followed in the adit levels for a 
distance of 2,310 ft., strikes in general about N. 43° E., and dips to the south-east at 
high angles. It varies in width from a mere seam up to about 20 ft., and would 
probably average 17 ft. 

The veinstone in the adits consists, in the main, of cellular or platy quartz, generally 
stained reddish-brown with hydrated ferric oxides, and containing much black oxide 
of manganese.* It is a quartzose replacement after a manganiferous calcite. Harder, 
finely crystalline, massive quartz, also oxidized, is present to a much less extent, and 
represents the filhng of fissures and irregular openings in the older shattered calcitic 
matrix or in the neighbouring wall-rock. The gold-silver electrum is present in this 
oxidized veinstone in an extremely fine state of di\'ision, and is seldom or never 
visible to the naked eye. Granular sulphides, pyrite, and argentite were observed 
in small unoxidized remnants of hard finely crystalHne quartz in the adit levels. Some 
of these small sulphide patches showed " mustard gold," probably the product of 
precipitation from descending auric solutions. Included in the mass of rust-stained platy 
quartz of the adit levels were observed one or two blocks of white crystalhne calcite, 
mere remnants of what originally constituted the whole of the vein-filling. 

The conditions which were found to exist below the adit level can only be gathered 
from old plans and records ; and from these sources the plans and sections included 
in this report have been prepared, and the general inferences have been drawn. 

The main ore-shoot persisted from the surface to a httle below the horizon of No. 5 
level, a vertical distance averaging 500 ft. The stope-length was longest at the adit 
(No. 1) level. Here it measured 760 ft., shortening somewhat towards the surface. 
At Nos. 2, 3, and 4 levels (see plan) the stope-lengths of the vertically pitching shoot 
proved fairly uniform — 400 ft. to 420 ft. — but below this a marked shrinkage is recorded, 
and at No. 5 level the ore was poorer, and extended over a stretch of not more than 
150 ft. The pitch of this deeper portion of the shoot was at a high angle towards 
the north-east. Winzing and driving below this revealed practically no ore. 

On the south-western trend of the reef, and near No. 2 shaft, several small blocks 
were stoped above or immediately below the adit level. The No. 2 level driven from 
the shaft named is said to have exposed mainly a calcitic vein-fiUing and no profitable 
ore. Beyond a httle drifting at No. 4 level, deeper explorations were not undertaken 
in this portion of the property. 

The general character of the ore has already been indicated. Referring to the 
main shoot, oxidation of the veinstone extended to a considerable depth, as might be 
expected from the cavernous nature of the quartzose veinstone and the general surface- 
configuration. At the No. 5 (500 ft.) level the existence of some oxidized loose quartz 
is recorded. The sulphide ore was probably associated rather with the more compact 
crystalhne quartz and replaced proyphte than with the more pervious pseudomorphous quartz. 

A feature of certain portions of the Golden Cross vein, even within the ore-shoot, 
was the existence of caves, due to the dissolution of the original calcitic matrix. One 
cave in particular, in the stoping-block between Nos. 1 and 2 levels, was very large, 
measuring from 20 ft. to 50 ft. wide, and over 200 ft. long. Caves in the calcite or 
quartz-calcite matrix generally showed walls of quartz — complete replacement of the 
carbonate, hence the record on mine-plan, " Quartz reef all round cave." Not infrequently, 

* In some of the ore treated in the mill nickel and cobalt were present in small amounts. 



Ill 

too, the floor of a cave contained " sedimentary material " — sand and black manganese- 
oxide — the less soluble constituents of the impure parent carbonate. 

The Golden Cross ore-shoot was evidently the result of the impregnation of 
sihceous ore-bearing solutions through a zone of fractured and fissured dacite, the 
openings in which had been previously filled by manganiferous calcite. Some of these 
bodies of carbonate were of large dimensions, those lenses still unreplaced at the 500 ft. 
level measuring up to 80 ft. wide. The ore-impregnation was apparently preceded by a 
reopening of the fissures, and a refracturing of the earlier-formed carbonate and of the 
contiguous wall-rock. The replacement of the carbonate by quartz has in places been 
complete, and again only partial, the plans submitted giving some indication of the 
complexity of the resultant mass. The action of carbonated surface-waters has also 
had an effect in removing murh of the carbonate that escaped replacement by ascending 
solutions. Crosscuts even in the upper levels revealed the existence near the main 
ore-bearing channel of heavy bands of calcite, or calcite but shghtly replaced. Drifts, 
after getting beyond the limits of the ore-shoots, moreover, frequently penetrated a 
mixture of quartz and calcite or massive calcite. Below No. 4 level, where the ore-shoot 
shortened, the calcite converged at each end of the stopes, finally cutting out both 
the quartz and the ore just l>elow the floor of No. 5 level. Mining developments 
below the 500 ft. level, moreover, have gone to show that these calcite bodies them- 
selves lens out rapidly in depth, and give place to rock exhibiting sheeted fracturing 
— numerous parallel joints, narrow fissures, and pug-filled shattered zones, in which 
little or no calcite or quartz has been deposited. No. 7 level drift gave no ore, and 
revealed but little quartz. Numerous small parallel stringers of quartz, however, 
ahgned with the general strike of the vein-system, were intersected. The plans will 
show the extent of the calcite exposed at the 700 ft. level. The amount is much 
less than at the 500 ft. horizon. 

Diamond-drilling was undertaken by the London company in 1903-4, in order to 
throw some light on the conditions existing below the 700 ft. (No. 7) level. The 
section prepared shows the projected positions of Nos. 1, 2, and 3 holes. No. 4 hole 
was sunk from the surface, and was projected at an angle of 37° from the vertical, 
to intersect the plane of the lode at a vertical depth of 1,200 ft., and at a point 
260 ft. northward of the shaft. " This hole was beset with difficulties from its 
commencement,"* and was abandoned after 1,105 ft. had been drilled. 

None of the boreholes, it is stated, revealed any veinstone, either quartzose or 
calcitic. No. 1 hole, which attained the greatest depth, after passing through soft 
and shattered country entered, at 800 ft., " harder and more brittle rock."* 

It is unfortunate that no survey for deflection was made of any of the boreholes, 
as greater reUance could then have been placed upon the data that the bores afforded. 
Having regard, however, to the exploration done, and also to the genesis of the 
ore-bodies, the deep-level prospects of the Golden Cross are anything but bright. 

The operations of the New Golden Cross Company are, as previously remarked, 
confined to opening certain blocks in the adit levels. A paragraph in the 1903 annual 
report of the Waitekauri Gold-mining Company, London, stated : " An effort was 
made to deal with the ore available at the upper levels, but it was found that the 
grade (18s. Id. per ton) was too low to cover the cost of production, and in consequence 
milling was suspended on the 18th July, 1902." The present proprietors have crushed from 
a small remnantal block of the main ore-shoot 351 tons, for bulhon valued at £1,097. 
None of the low-grade material available will be treated until the ten-stamp mill is erected. 

Grace Darling Claim (old). — The Grace DarUng Claim (now abandoned) is situated 
on the western side of Grace Darling Stream, the main tributary of the Waitekauri, and 



* Mines Report, C.-3, 1905. 



112 

just below the junction of Kathleen Creek. The lowest of the several adits is only 
about 70 ft. above the level of the stream-bed. 

The claim included older holdings, kno^vn as the Portsea, Prioress, Pyramid, 
Vendor, and Progress, and was worked »at various times between the years 1893 and 
1906. A considerable amount of capital has been sunk in exploiting the ground, and 
no less than three batteries (one equipped with a cyanide plant) have at different 
times been erected and dismantled. The following figures are sufficiently indicative of 
the failure of the several ventures : 1894--1900 — Tons crushed, 1,641 ; value of peld, £692. 
1905-6— Tons crushed, 22 ; value of yield, £50. 

The workings have been confined to one reef, ranging in ^vidth from a few inches 
up to 20 ft., with an average of, say, 4J ft. The strike is about N. 5° W., and the 
dip eastward at angles averaging 70°. The enclosing rock is a fairly soft propyhtized 
andesite, grading some little distance beyond the foot-wall of the reef into harder, 
less-altered rock, seamed with quartz and calcite stringers. Certain of the drifts on the 
reef measure over 800 ft. Rise connections have been made, and some stoping has 
been done. The veinstone, which is completely oxidized, is largely a quartzose replace- 
ment after a manganiferous calcite. It exhibits the usual coralhne, vesicular, and platy 
forms characteristic of this type of deposit, in addition to stainings of iron and 
manganese oxides. Solid finely crystalhne quartz (direct fissure-filhng), crushed wall- 
rock more or less siUcified, and a good deal of clayey material are also present. 
Reports state that finely divided free gold was occasionally visible, but that, on the 
whole, the ore only occurred in very small isolated pockets, and had no general distri- 
bution throughout the veinstone. 

The " prospect " is a very poor one, and, judging by the genesis of the deposit and 
the occurrence of calcitic veinlets in the harder wall-rock, explorations at greater depth 
would reveal a veinstone consisting largely of a barren calcitic matrix. 

The Durbar Claim (old). — The Durbar Claim (now abandoned) is situated on the high 
ridge (elevation, 1,700 ft. to 1,850 ft.) forming the water-parting between the Komata 
and Waitekauri valleys, and near Durbar trig., at which point the graded road crosses 
from the one valley to the other. 

The claim covers a portion of the old Alpha holding, and the ground has been 
worked from time to time since the year 189-1. Several adits, which intersected reefs, 
have been driven at different elevations both from the Waitekauri and the Komata slopes 
of the ridge. The lowest of these adits is about 600 ft. below the crest of the ridge. 

A twenty-stamp mill, with a cyanide plant, was erected by the Alpha Company in 
1899, but was closed dowai after 965 tons had been crushed, for bulhon valued at £711. 
This mill was subsequently removed. In 1907-8 the Durbar Company raised and 
carted away for treatment 193 tons, for returns totalhng about £350. 

The rocks of the locaUty consist of greenish-grey andesitic lavas and well-consohdated 
breccias, many of the latter being probably brecciated flows (autoclasts). In the vicinity 
of the reefs these rocks are more propyhtized. 

Quartz veins are numerous, and vary in width from a few inches to 4 ft. These 
strike in directions varying from N. 15° E. to N. 50° E., and have a persistent dip to 
the south-eastward at high angles, implying a sheeted Assuring of the enclosing rock-mass. 
The veinstone is oxidized, and consists almost entirely of the cavernous, platy, and 
coralhne quartz, stained with iron and manganese oxides, which has resulted from the 
replacement of a manganiferous calcite. Massive crystalline quartz is associated in small 
amount with the pseudomorphous material. As in the Grace Darhng reef, the gold- 
silver content throughout all the Durbar veins is very low, the ore existing only in 
small erratic shoots and isolated pockets. 



7h artiompany Sulliitin 3"* f5 



GOLDEN CROSS CLAIM, WAITEKAURL 

PLANS AND SECTIONS OF N? I REEF. 

Gjvering the locality of the main ore shoot. 

(from old mine records.) 

Scale of Feet 




118 

No remnant of the parent calcite was observed in any of the reefs ; but from the 
evidence afforded by the Te-ao-marama tunnel, driven from Grace Darling Creek, and 
which penetrated the ridge about 20 chains northward of the Durbar workings, the 
replacement quartz gives place to calcite at this horizon. 

Huanui Claim (old). — The old Huanui Claim is situated in the high country at the head 
of Huanui Creek, Waitekauri, and is less than half a mile south of Durbar trig. It 
was worked intermittently by a local syndicate between the years 1899 and 1907. In 
1901 a parcel of \^ tons of picked ore was treated, for buHion valued at £29 15s. 7d. 

The country rock of the claim consists of the same greenish-grey andesitic lavas 
and well-con-sohdated breccias as occur in the low-level Te-ao-marama tunnel (penetrating the 
Waitekauri-Komata Range), and which have considerable development between here and 
Maratoto. The rock near the reefs is, as may be expected, more altered, and of lighter colour. 

The workings, which have all collapsed, were confined to three adits at different 
levels. One main reef, varying in width from a few inches to 3 ft., and also two or 
three smaller leaders are reported to have been worked. 

The veinstone on the dumps is identical in general character with that of all the 
upper Waitekauri and Komata reefs — mainly a quartzose replacement after manganiferous 
calcite. It is all ox'dized, and is stated to have occasionally shown a colour of gold. 
Although a considerable amount of drifting and rising was done on the main reef no 
profitable ore-shoot was discovered. 

The old Waitekauri Claim (area, 9 acres 2 roods 23 perches ; owners. New Waite- 
kauri Oold-mining Company, Limited, Auckland). — The old AVaitekauri Claitn is situated 
on Jubilee Hill, about 60 chains south-west of Waitekauri Township. Within the 
boundaries of the claim was discovered, about the year 1875, the first payable gold in 
this district. Work has been carried on intermittently ever .since, both local and English 
capital having been employed. The total output is not recorded, l)Ut is stated to 
approximate in value £120.000. The following figures are available : 1887-96 — Ore crushed, 
5,253 tons; value, £1,154. 1902 6^0re crushed,* 3.."i03 tons ; value, £1 1,889. 1907-10— 
tvie crushed, 759 tons ; value, £1,293. Totulsr— Ore crushed, 9,535 ton.s ; value, £14.336. 

The claim has been worked altogether from adits, the vertical height from the main 
(Horn) level to the outcrop being 450 ft. The main reef strikes about N. 50° E., and 
dips about 57° to the north-westward. At the horizon of the Horn level — in places a 
short distance above, and again a short distance below — the main reef dips out of the 
old Waitekauri into the Jubilee Claim, the boundary separating the properties being 
nearly parallel to its strike. The prospective value of the old Waitekauri property, as 
far as the parent vein is concerned, is therefore practically nil. The proprietary company 
owns the old forty-stamp mill, with a cvanide plant, operated l)y water-power, which 
was erected by the Waitekauri Gold-mining Company, London, in 1896. 

The rocks of the claim — in fact, of the whole Jubilee Hill — are profoundly altered 
(propyhtized), and it is difficult to obtain specimens which reveal their original character. 
They are evidently andesites, with a somewhat dacitic facies. In the workings which 
were accessible flow rocks greatly predominate, but thin beds of breccia appear to be 
present. In the Jubilee Creek, which skirts the hill on the north side, some verv heavy 
altered breccias are observable. Such a fragmental complex would afford country rock 
distinctly unfavourable for ore-deposition in veins which might intersect it. It is, 
however, doubtful from the section available whether these breccias would or would not 
be found at deeper levels in the Jubilee Hill area. 

In addition to the main reef, the disposition of which has already been indicated, a 
hanging-wall loop vein (called Butler's) and a branch vein (called Christie's) have been 



• Approximate ; crushed with ore from the Golden Cross Claim. 

8— Waihi-Tairiu. 



114 

worked. The main reef has been followed for over 1,700 ft. at the Horn level, when 
on its south-western strike it finally entered the Jubilee Qaim. The shallower adits are 
shorter, depending on the contour of the hill. In width the vein would probably average 
about 7 ft. or 8 ft., but it is decidedly lenticular, in places contracting to a mere seam, 
and again widening suddenly to 10 ft. or 12 ft. The veinstone consists, in general, of 
white or bluish-white, massive, finely crystalline quartz, but much of it is rubbly and rust- 
stained, and includes a considerable amount of crushed countrj' rock. Pseudomorphism 
after calcite is only occasionally observable, and \iigs and cavities are, on the whole, 
small and inconspicuous. The veinstone carr^-ing sulphides, which is more conspicuous 
at the lower levels, frequently presents a concentric banded structure. Pyrite and 
chalcopyrite are the predominant sulphides, and with these are associated a little galena 
and zinc-blende, and occasionally argentite. The total amoimt of sulphides, even in the 
more highly mineraUzed streaks and lenses, would probably aggregate less than 2 per 
cent. The gold-silver content of tWs sulphide veinstone is low, although a small block 
on Cliristie's reef, near its junction with the parent vein, carried payable ore. 

The main ore-shoot worked in the old Waitekauri Claim extended from the outcrop 
or " Blufis " portion of the vein down to within 90 ft. of the Horn level, a vertical range 
of about 360 ft. In this locality occurred Butler's hanging-wall loop vein. Below where 
this loop junctions in dip with the parent reef the ore has proved unprofitable to mine, 
the highest assays yielding, it is said, about 17s. per ton. The stope-length on the ore 
did not exceed 200 ft. Beyond the Umit of this shoot small lenses of ore were dis- 
covered, but the returns from these did not nearly repay the cost of mining. 

A notable feature in connection with the Waitekauri reef is the presence, particularly 
along certain stretches on the hanging-wall side, of soft shattered rock with much puggy 
material. The veinstone along these stretches is almost invariably of low value ; further- 
more, the ground is very heavy, and necessitates substantial timbering. 

No work is now being done on this property. 

The Scotia Claim (area. 25 acres 1 rood 10 perches ; owners, the Scotia Gold-mining 
Company, Limited, Auckland). — The workings of this claim are situated on the eastern 
side of the Jubilee Hill, and only a short distance from the main road connecting 
Waitekauri Township with Waikino. 

The ground has at various times been worked on a hmited scale by private indi- 
viduals and syndicates. The Scotia Company was not formed until 1909. Statistics 
available show that from 1906 to 1910, 388 tons of ore yielded 610 oz., valued at £967. 
■ The coimtry rock of the workings, which are opened from shallow adits, is a some- 
what weathered coarse-textured propyhte, resembUng an altered dacite or dacite-rhyoUte. 
No less-altered remnant which would reveal definitely its original character was obtain- 
able. The block of country enclosing the workings is on approximately the northern 
trend of the Owharoa dacite-rhyohte, and it is not unhkely that the Scotia rocks may 
represent a somewhat less acidic differentiate of the same magma. 

The quartz veins vary in width from 2 in. to about 2ift., and usually dip at low- 
angles — 30^ to 40°. The veinstone, which is practically all oxidized, consists of friable, 
white, and rust-stained quartz, with some admixture of crushed propyhte and clayey 
material. The gold-silver electrum is present in a very fine state of division, and has 
apparently been released from sulphides by oxidation. Small patches, carrying finely 
granular bluish-grey sulphides as small nests and narrow streaks, are recognizable, and 
occasionally give on assay fairly high values. Argentite is present in tliis sulphide ore. 

The claim seems capable of affording a small amoimt of ore, which should show a 
margin of profit if better facilities for transit and treatment of the ore were available. 
Only further prospecting and developmental work will, however, show whether the ore- 
shoots of the various veins are sufiiciently extensive to warrant expenditure in the 
direction indicated. 



115 

Jubilee Claim (area. 161 acres 2 roods 19 porclies ; owners, the New Zealand Jubilee 
Gold-mine, Limited, London). — The Jubilee Claim is situated on the Jubilee Hill, and 
lies to the south-west, and almost surrounds the old Waitekauri Claim. 

Since 1889 the gromid has been owned and intermittently worked by the Jubilee 
Syndicate, London. A considerable amount of money has been spent in crosscutting and 
drifting, and in connecting various levels. Veinstone broken out during the course of 
tliis work has been stacked, but apparently httle of it can be classed as profitable ore. 
Only a few small parcels have been treated, and, as the material was mostly hand-picked 
from the dumps, the results bear httle significance. The output from 1887 to 1910 is 
as follows: Ore crushed, 2,118 tons; bullion produced, 1,292 oz.; value, £3,019. 

Practically all the work done has been confined to the main Waitekauri reef. The 
Horn adit, which is on or about the horizon where this reef dips from the old Waite- 
kauri Claim into the Jubilee Claim, has already been mentioned. It was driven 
conjointly by the two proprietary companies. A further extension of this diift beyond 
the south-western boundary of the old Waitekauri ground was undertaken by the Jubilee 
Company. Vertically 250 ft. below the Horn level is the Jubilee adit, 4.500 ft. in 
length, the inner 3,250 ft. of wliich is drifted on the Waitekauri reef. At 500 ft. from 
the entrance of the adit a connection was made between this and the Horn level. 

In the low level both the country rock and the reef present the same general 
characteristics as described in connection with the old Waitekauri Claim at the Horn 
level above. The heavy slidy countiy in contact with the hanging-wall of the reef 
persists here, and the vein is of the same lenticular form, altliougli, on the whole, it is 
wider than at shallower horizons. Widths up to 32 ft. have been recorded. Sulphide- 
bearing veinstone is more conspicuous in the Jubilee adit than at the levels overhead, 
but it is still, in the main, of bunchy and lensoid occurrence. Some of the concentric- 
ally banded cupriferous material, although of attractive appearance, has a singularly low 
gold-content. An assay of a dump specimen taken by the writers jHelded — Oold, traces ; 
silver, 4 oz. 19dwt. 11 gr. ; value, 9s. lid. per ton. A stretch of the hanging-wall 
portion of the vein, meiisuring about 300 ft. in length and occurring about vertically 
imder the entrance to the Horn level, has shown brokenly continuous l)ands and irregular 
bunches and lenses of sulphide veinstone. Copper-pyrites and its decomposition-products 
are conspicuous ; a httle galena and zinc-blende are also present. Prospecting-rises have 
here been constructed for about 70 ft., and it is considered by the management that a 
block of ore assaying about £2 5s. per ton exists. Owing to the heavy volume of water 
to be raised, sinking to prospect the vein was impracticable with the facihties available. 
No other ore-shoot was exposed in the whole course of this long drift. In the south- 
western end of the Horn level (250 ft. above), however, a shoot of sulphide ore measuring 
60 ft. on the horizontal is reported to exist, the width of the reef here being 3 ft. 6 in. 
This portion of the workings was inaccessible at the time of the writers' examination. 
The Jubilee level has not been extended far enough to meet this shoot if it persists 
downwards, but a surface adit is being constructed on the south-west side of the hill to 
prospect the reef on the line of its upward extension. The record of the Jubili-e 
Compan3''s adit-lcvel mining, as well as of the Waitekauri Company's developmental 
work at the Horn level, has been such a poor one that the advisabihty of any attempt 
to undertake still deeper exploration by sinking is, without further data, open to question. 
The character of the veinstone of the Jubilee-Waitekauri reel renders it more adaptable 
for testing at a depth by means of the diamond-drill than are the reefs, say, of the 
Waihi Goldfield. The judicious expenditure of a small amount of capital in this 
direction, particularly where there are indications of shoots of sulphide ore existing, 
has more to recommend it than the intermittent and casual expenditure of money at 
the adit levels. 

8 •— Waihi-Tairua. 



116 

Maoriland Claim (area, 120 acres and 20 perches ; owners, Maoriland Gold-mining 
Company, Limited, Waihi). — Tlio Maoriland Claim is situated south-west of Jubilee Hill, 
about 50 chains from the trig, station, and Hes within the valley of the Mangakara 
Creek, a tributary of the Waitekauri. 

The claim includes, among other older holdings, the ground formerly known as the 
Young New Zealand, which afforded in the earlier days of the Waitekauri field rich 
outcrop ore to the value of £2i,000. This outcrop ore was mined from opencuts and 
shallow levels. Since the year 1887 the returns have been small, as the following figures 
will show : — 

Tons Yield, 

crushed. £ 

1887-99. Young New Zealand Company . . . . 26 171 

1906-10. Maoriland Company .. .. .. 2,001 3.104 

In addition to the original surface cuttings, all prospecting and mining work has been 
done from adit levels. The Maoriland Company is working from two levels, vertically 
148 ft. apart, the lower of which is connected by tram with a nine-stamp mill and 
cyanide plant erected on Mangakara Creek, and operated by water-power. 

The country rock of the claim consists of irregularly stratified beds of andesitic and 
dacitic lavas and tuffs, all in an advanced state of propyhtization. Principal economic 
interest is centred on one particular bed of dacitic breccia, which in places outcrops at 
the surface. The base of this bed presents forms simulating antichnes and syncUnes, or, 
to use the miner's expression, "' a rolhng structure." It is, moreover, separated from 
the underl\ang rocks by a band of sUdy or puggy material, suggestive of differential 
movement. This dacitic breccia, wliich consists of fragments which seldom exceed |in. 
in diameter, and shows occasionally small inclusions of carbonized wood, has been 
impregnated throughout by mineral-bearing solutions, which have resulted in its siUci- 
fication and pyritization. The gold-silver content of the general mass of this minerahzed 
breccia is, however, very low, assays of rough samples showing only 6 gr. of gold 
and 3 dwt. 12 gr. of silver per ton. 

The vein formation — the Maoriland — that has given the greater part of the gold won 
from the claim is confined entirely to the mineralized breccia - band just described. 
Veins have also been located in other portions of the rock-complex, and from the 
Welcome and other of these gold-yields have been recorded. 



Silicified and pyntised 
dacitic breccia 




,™ ,,, ^N9S Level 

A < ■ ^ " '^ /' ^ 



<, 4 



4 I ' ^7^"^ 



0°^ ^ \3^ 



'57^:/ ..X 



A 



A 



Pro0 



^ '" "-- 1^ icS>^ 

^ ^n'i ^ ^ '^ Scale of Feet 

^ 6 ^ ^ /v T,,,,i.,M? 'r ^° 



liti^e' 



A- 



Low- level crosscut projected Trom old driTl- 
Diagrammatic Section showing Geological Structuke ix Maoriland Claim, Waitekauri. 



117 



Tile Maoriland vein formation, which strikes about N. 20° E., and dips westward at 
angles approximating 75°, is a fairly well-defined fracture-band in the breccia, along 
wliich a more pronounced mineralization has taken place than in the general mass of the 
breccia itself. The main fracture-plane forms the hanging-wall of the ore-body, and a 
defined foot-wall is seldom or never recognizable, the ore within the shoot grading into 
practically non-auriferous breccia at distances of from 4 ft. to 14 ft. from the hanging- 
wall. Within the ore-band the breccia is highl)- sihcified, and consequently hard. 
Pyrite, as small bands and patches and as concentric crusts surrounding included frag- 
ments, is fairly abundant. Small veinlets and bunches of crystalline drusy quartz are 
also present. The proven shoot of ore is of no great extent, and its value on treatment 
seldom exceeds £2 per ton. The existing low level (an extension of an old adit), 148 ft. 
vcrticallv below the level known as No. 3, penetrated country lying below the horizon of 
the dacitic breccia-bed, and no counterpart of the ore-bearing vein formation was found 
to persist here. A winze sunk on the ore-shoot was then found to pass through the bed 
at a depth of 60 ft. or 70 ft. below No. 3 level, and from an intermediate level here 
stoping is proceeding. 

There can be no question that the rich surface-patch worked in the early days, and 
known as " Hollis's Blow," occurred in the dacitic breccia, and was but a supcrlic ially 
enriched northern portion of the vein formation now being worked by the Maoriland 
Companv. The failure to recognize the structural conditions led to much money being 
expended in endeavouring to locate the vein formation below tliis " Blow." 

Of the Welcome and other veins httle can be said, as the workings are now 
inaccessible. The Welcome reef is stated to have averaged 9 in. wide, and showed signs 
of increasing strength with depth. The veinstone was heavily pyritized. and the ore- 
shoot worked yielded crushing-mate r.al worth from £2 to £3 per ton. 

The value of the claim, apart from the ore-shoot now being worked, is purely a 
prospective one. It may be mentioned that the lateral limits of the silicified dacitic 
breccia-formation, which has so far proved the most productive, have towards the east- 
ward not yet been determined. Ore-bands in addition to the one being worked may 
exist in unexplored portions. 

OWHAROA. 

Mining at Owharoa dates back to the earliest years of the Ohinemuri Goldfield, l)ut 
unfortunately there are no records of the gold-silver output prior to the year 1887. 
Since the year named the available statistics are as follows : — 



Year. 


Claim. 


Crushed. 


Yield of 
Bullion. 


Value. 






Tons. 


Oz. 


£ 


1887-95 


Smile-of-Fortuiie 


4,607 


2,411 


3,301 


188S 


Me and Rowe ... 


60 


7 


9 


1891-96 


Madden's Folly ... 


269 


55 


70 


1892 


Vertus ... 


1 


6 


13 


1892 


City of Glasgow 


26 


7 


10 


1894-95 


Cadman 


472 


120 


140 


1896 


Owharoa 


480 


45 


56 


1903-8 


Rising Sun 
Totals 


53 


148 


125 




5,968 


2,799 


£3,724 



It is stated that the value of the gold-silver output probably totals £50,000. 
The vein-bearing rock of this portion of the field is unhke that of any other part 
of the subdivision, being a spheruhtic rhyoUte or dacite-rhyohte referable, it is beUeved, 



118 

to the " First rciiod." Rhyolitic rocks belonging to the earUer phases of Tertiary 
vulcanism have, in the country examined by the writers, only been found in the Coro- 
mandcl Subdivision, where they directly overUe the coal-measure strata in the head- 
waters of streams draining into Cabbage Bay. They are also reported by McKay* to 
be involved in the structure of Karangahake Mountain, Hang about two miles to the 
south-west of Owharoa. In the area now imdcr review the rhyohtes have been com- 
pletely altered by hydrothennal action, and usually present a rather coarse-textured 
granular appearance. 

Practically the whole gold-peld of Owharoa has been derived from sheared zones 
or bands in the dacitic rhyohte, the total wdtli of the belt enclosing the ore-bodies 
being about 500 ft. These bands of mineraUzation resembled the stock-work tj-pe of 
deposits, each including numerous parallel stringers and erratically disposed streaks and 
bunches of quartz and much soft mineralized country rock, the whole of the material 
being more or less auriferotis. The principal Unes of mineraUzation were kno'mi as 
the Smile-of-Fortune and the Radical Nos. 1 and 2 reefs. Each of these had a general 
strike of N. 25° E., and ranged in thickness from a foot or so to about 12 ft. The 
oxidized ore of the opencuts and shallower adits proved profitable ; but the vein- 
material exposed by the lower adits and winzes was, vnth. the exception of a few small 
shoots, unprofitable to mine. In 1897 a shaft (size, 12 ft. by 6 ft.) was smik by the 
Ohinemuri Syndicate, to a depth of 150 ft., close to the north bank of the Ohinemuri 
River, the intention being to further exploit the Sraile-of-Fortmie and Radical reefs, . 
and to prospect for other ore-bodies. At 125 ft. from the collar of this shaft crosscuts 
were projected, and several veins were intersected. Certain of these were thought to 
correspond with the ore-bodies worked in the adits, but their identity was not proven. 
From one or two of these veins " a httle gold w^as obtained, but not in payable 
quantities."! Shortage of fimds to carry on pumping and further prospecting-work 
caused the abandonment of operations in 1899. 

The same syndicate also drove what was known as Elliot's tunnel from Mangakara 
Creek to prospect coimtry on the general trend of the main Owharoa veins, although about 
100 chains northward of the Owharoa workings. In a small gully in this vicinity, it 
may be mentioned, detrital gold was obtained in earher years by sluicing, but its origin 
could never be traced. Although some 2,764 ft. of crosscutting was done (750 ft. of 
this is reported to be in the overlying Pliocene rhyohtes) no reefs were discovered, and 
the project was abandoned. This tunnel is not now accessible. 

The only claim at present working at Owharoa is the Rising Sun. 
Rising Sun (area, 158 acres 1 rood 21 perches ; owners, tbe Rising Sim Gold- 
mining Company, Limited, Auckland). — This company's property comprises the Rising 
Sim, Rising Sun Extended, and Inglewood claims, and Hes immediately to the north and 
west of the Smile-of-Fortune and Radical groimd. The Ohinemuri River forms the 
southern boundary of the Inglewood Claim. 

Operations have been in progress since the year 1896, but the output so far is the 
result only of two trial crushings — 53 tons of ore ha\'ing yielded 148 oz. of bulhon, valued 
at £125. 

The country rock is the altered dacite-rhyohte, pre\'iously mentioned. It fre- 
quently exhibits spherulitic structure, and at the more oxidized surface horizons is of 
a rather gritty almost pisoUtic nature. In places the workings require substantial 
timbering. 

One main reef mth several loop and branching veins has been exposed in the 
workings, which comprise two adit levels, spaced at about 60 ft. and 150 ft. respectively 

* Mines Report, C.-9, 1897. f " Rocks of Cape Colville Peninsula," vol. 1 p. 104. 



119 

below the highest i)oint of outcrop. In the No. 2 or lower of these adits the reef, 
which strikes nearly north-south and dips to the westward, has been followed for about 
•180 ft. It varies in width from a line to 5 ft., and probably averages about 18 in. Here 
and there the veinstone carries lenses and bunches of ore, black and greyish-black streaks 
of pyrite and argentite rainifyiiig through the milky-white iincly crystaUine (juartz. Gold 
is occasionally visible in association with the sulphides. The main ore-shoot occurs near 
the north end of the workings, and has been followed by wiuzing for about 90 ft. 
From the 60 ft. mark in the winze an intermediate level has been driven about 70 ft. on 
the reef, w^ithout disclosing the longitudinal limits of the pay-ore. The reef is more 
compact, stronger, and promising-looking in the winze-workings than at the No. 2 level, 
where the fissure appears weak and, in places, indefinite. 

At present work is confined to driving a low-level adit from the main road skirting the 
Ohincmuri River. This level, which will afford "backs" of about 150ft. below No. 2 
level, was advanced 1,500 ft. at the time of examination, and a further (iOOft. should 
bring it under the winze. Unfortunately, this long adit is approximately parallel to the 
general hue of strike of the Owharoa veins. In addition to the exploiting of the ore- 
shoot already located, however, the systematic prospecting of the coiuitry both to the 
east and west imiy now be readily effected by offset crosscutting. 

Ma( KAYTOWN. 

The country in the vicinity of Mackaytown rises abruptly from the base of the 
Ohinemuri River valley to the high wooded range intersected by the Karangahake 
Gorge. The andesites and dacites are here apparently referable to the '' Second 
Period." 

Deposits of siliceous sinter are widespread, and, on account of the resistance they 
have offered to erosion, form the capping of conspicuous hills. Some of these white 
quartzose outcrops led to claims being staked by the prospector in search of gold, but 
subsequent results were not encouraging. The gold-silver content of the sinters rarely 
exceeds in value 2s. or 3s. per ton. 

As in the Kauaeranga Valley, Thames (sec Bulletin No. 10. pages 65 6(5), cinnabar 
is associated with certain of these sinters. The known cinnabar-deposits he within the 
Ascot Claim, about to be described. 

The Ascot Cinnabar Mine (area, 177 acres 3 roods ; owners, the New Zealand 
Cinnabar Company, Limited). — The occurrence of cinnaijar in this locahty has been 
known for many years, and several unsuccessful attempts have been made to exploit 
the deposits. A plant has recently been erected by the owners, and small (juantitics of 
ore have been treated, but the extraction so far has hardly proved satisfactory. The 
plant consists of a furnace of the Norah Shaft type, 21 ft. by 8 ft. inside-measurement, 
and various forms of condensers and accessories. 

The cinnabar, as remarked, occurs associated with the siliceous sinter. The sinter 
sheets or beds dip northward at angles of from 10° to 15° and, together with the propy- 
htizcd andesites. form a small hill having a steep scarp to the southward. 

At the locahty of the principal excavation there appear, underlying a heavy layer 
of decomposed surface debris, two fairly well-defined sinter-beds. The upper bed is 
about 10 ft. thick, and the lower one probably averages 20 ft. thick. Between these 
beds a band varj-ing considerably in width occurs. This band consists of rusty or 
whitish kaohnized propyhte, and in places contains much sinter. It represents the 
principal ore-bearing horizon. Below the lower or 20 ft. sinter-bed a tunnel, driven 
northward from the hill-scarp to intersect the ore-bearing horizon, exposes whitish 



120 

propylitc enclosing throughout irregular rounded and lensoid masses of sinter, but this 
material contains no ore. 



E.)ic^vdtions 



On floor and roof in pbce,s ^^ 




Upper sinter bed 



Lower sinter bed 



" 5 Kaoimized country, more or less 
n ^ iinteriied, arid inploces alrnost 
cut out end replaced bj sinter 



Lower drive 



Decomposed cow/try, more or less Sinierized 

Fio. 1. 
Diagrammatic Section of the Siliceous Sinter-complex. 

The sinter is usually dense and jas2)eroid, but in places is pitted and honeycombed, 
some of the cavities being lined with drusy quartz. A banded structure is not 
uncommon. It is generally dark-coloured, often black, but in places whitish. l)rownish, 
or reddish. The blackish sinter is frequently highly pyritous. and, within the range 
of oxidation, rusty. 

The cinnabar is chiefly associated with fractures, ramifying veinlets, and geodes 
in the sinter and in the silicified propyhtc. It is in many places accompanied with 
whitish flinty quartz. In the neighbourhood of such fractures the cinnabar is occasion- 
ally found impregnating the sohd sinter itself. As already stated, the propyhte-band 
which separates the two more-defined sinter-beds, and is in places highly sinterized, con- 
stitutes the main ore-bearing horizon. Here a somewhat persistent fracture exists just 
above the lower (20 ft.) sinter-bed, and preserves the same general dip as the lieddcd 
complex. This fracture or vein, which usually contains drusy quartz, cinnabar, and a 
good deal of yellowish clayey material, is of irregular width, contracting in places to a 
mere seam, and again widening to a foot or more. With it occur more or less vertically 
disposed lenticular seams, which are also clay-filled and cinnabar-bearing. 



^ Bfe^ 




Fig. 2. 
Showing Modes in which the Cinnabar occurs in the Siliceous Sinter. 
1 and 3. Cinnabar in whitish flinty quartz. 
2. ,. rusty puggy seam. 

4. ,, rusty puggy-filled cavity. 



Assays of the cinnabar-ore and the associated sihceous sinter revealed gold and 
silver to the extent of only a few grains per ton. 

The sihceous sinter of this locaUty and of the " Big Blow," overlooking Rahu Creek, 
is evidently the deposit of hot springs, the waters rising to the surface probably through 
a fault-plane. As the cinnabar is confined to local fractures, veinlets, and nests and 
their neighbourhood, the metal-bearing solutions were evidently of later origin than the 
waters which deposited the mass of tlie sinter. The cinnabar, together with pyrite and 



121 

some quartz, was deposited in bands of permeable propylito iiichidcd in the sinter- 
complex and in the lissures and cracks in the sinter itself. Possibly some of the clayey 
material containing loose crushed cinnabar has migrated mechanically, through recent 
fractures, from superficial horizons. Fairly rich ore exists in places, but usually the 
cinnabar is of sporadic occurrence. 

It seems reasonable to suppose that the portions of the ore-bearing horizon exploited 
by drives and opencuts is fairly representative of the whole deposit. The deposit is 
therefore hkely to be everywhere irregular and patchy. 

Waihi Beach. 

The Waihi J5each mining area is situated on the coast-lmc about six miles due east 
of Waihi Town. Until recently the area was served only by horse-tracks, but a 
well-graded road now leads to the beach from Waihi. 

The Waihi Beach and Taipari are apparently the only claims now held in the 
district, though originally prospecting was done on several others. The existence of 
quartz veins here was known as early as 1870, when the locality was visited by the 
late Sir James Hector. Some prospecting was done during the period 1894- 'J6, but 
it was not until I8!)8. when an amalgamation of interests took place, that any exploration 
worthy of note was attempted. Since that date a consideraiile amount of driving 
has been done, and a shaft has been sunk on the Waihi lieach propertv. Tiie area 
enclosing all the workings is small. 

From the northern end of the long .sandy Waihi Beach, bush-dad hills rise some- 
what abruptly from the seashore. It is on the lower slopes of these, and for the most 
part where steep chffs abut against the ocean, that the greater part of the mining 
exploration has been done. 

The geology of the locahty is distinctly complicated. rrobal)ly the most wide- 
spread rocks of the immediate vicinity are rhyohtic breccias, consisting mainlv of fine 
fragmental material. In many places these breccias are liighly silicified and pvritizcd. 
They overlie pyroxene - andesites, usually remarkably compact and fine-grained, and 
not infrequently cxliibiting a glassy lustre and a distinct flow structure. In places, 
especially in Orokawa Creek, the ande.sites are locally brecciated. The oxidation of 
these altered and highly pyritized andesites has given rise in many places to very 
rusty outcrops. 

The andesites and rhyolitic breccias are cut by rhyohtes, which are also highlv altered, 
and cannot always be readily distinguished from the intruded altered andesites. These 
rhyohtes are generally spheruhtic, and exliibit well-marked flow structures. Metallization 
in this area has, in the main, post-dated the period of intrusion of the flow rhyohtes. 

Alluvial gold in small quantities can be obtained from nearly all the creeks from 
Waihi Stream northward to Fraser Creek, which enters Hoinunga Bay. In the last- 
named creek detrital cinnabar was also found. Apparently most of the gold in the 
creeks north of the Waihi Beach Claim is shed from the mineralized breccias. 

In the andesites, generally close to the contact with the rhvolitic breccias, pyritized 
sihcified bands or zones have an extensive development all the way from Waihi Stream 
to Fraser Creek. They arc especially conspicuous in the Taipari ground, on either 
side of Waihi Stream ; in various places within the Waihi Beach Claim ; at the head of 
the two most southerly streams entering Orokawa Bay; in Te Puru Stream; and in 
Fraser's Creek, Homunga Bay, not far above Pennel's house. The.se zones, which 
usually range up to 5 ft. or more in width, are all of the same character, consisting 
mainly of shattered and brecciated belts of andesite that have been cemented by 
flinty or more coarsely crystalhne quartz. They carrj- a considerable amount of 



122 

pyrite and greenish marctisitc, and their outcrops arc generally marked by limouitic 
gossans. What is probably one continuous zone extends in a general direction of 
N. 70° E. from Taipari Claim into the Wailxi Beach Claim, and is here known as the 
" main reef." On this zone some prospecting has been done in the form of cross- 
cutting and drifting, but no ore appears to have been discovered. Samples taken by 
the writers proved on assay to contain no gold or silver. Veins occur also in the 
intrusive rhyolitcs. These occur principally in the Waihi Beach claims about to be 
described. 

Waihi Beach Claims (area, 315 acres 3 roods 3J: perches ; owners, the Waihi 
Beach Gold-mining Company, Limited, Auckland). — The Waihi Beach claims are situated 
principally on the bold coastal headlands lying immediately northward of the long sandy 
Waihi Beach. 

The company started work about the year 1899, with the object of exploiting 
the Treasure Island and other reefs which were known to exist. A 2-ton parcel from 
the reef named, taken out by the original prospectors (Shaw and party), had yielded a 
return of £14:. The company, after doing some further prospecting from adit levels, 
sank a shaft on the headlands to a depth (below the collar) of 355 ft., and equipped it 
with winding and baiUng plant. Little water was encountered in the workings, although 
they were considerably below sea-level, until a big water-bearing cross-course was inter- 
sected in one of the drifts, and caused cessation of mining operations. A considerable 
amount of money was squandered in futile attempts to unwater the workings with 
small steam-pumps, and the company has now gone into hquidation. 

The Treasure Island reef is, in addition to the minerahzed zone or " main reef " 
mentioned in the general description, the one that has received most attention. It 
strikes about N. 30° W., intersects spheruhtic rhyohtes, and dips at high angles to the 
eastward. From a winze sunk on its outcrop near the base of the coastal chffs, 
Shaw's parcel of picked ore was obtained. The veinstone here was a bluish-white 
fine-grained quartz, and showed some free gold. The reef appears again on either side 
of the small bay just north of the coastal cliffs mentioned, and has been followed in 
adits for short distances north and south. About 30 ft. to the north it is stated to 
have been completely cut off by a fault, which is traceable on the surface just above 
the drive. These workings are not now accessible. A rough sample of the veinstone 
exposed for a Avidth of about 20 in. on the foreshore gave on assay — Gold, 9 dwt. 17 gr. 
per ton ; silver, 1 oz. 9 dwt. per ton. 

In the shaft-workings the length of drifting on the reef totals 1,017 ft., of wliich 
861 ft. is north of the shaft crosscut. The vein throughout this latter stretch is said 
to have averaged about 3 ft. wide. The veinstone, which has been sampled* every 
5 ft., is worth, according to the assays* made, shghtly less than £1 per ton, wdth 
occasional patches of ore worth from £2 to £3. South of the crosscut the values 
are reported to have been equally low. No stoping was done. 

The veinstone consisted of finely crystalhne quai*tz, often curly and crustified, and 
platy or lamellar quartz, pseudomorphous after calcite. Limonitic and black oxide of 
manganese stainings were conspicuous throughout, and there is in places a considerable 
admixture of mineralized wall-rock. 

It is rather remarkable that the genesis of the Waihi Beach veinstone, which is 
enclosed in Phocene rhyohtes, appears to be closely analogous to that of the older 
veins of Waihi, Golden Cross, and Komata, enclosed in andesitic rocks. 

* Information supplied by the company. 



123 

The Waihi Golufield. 
Introduction. 

Waihi ranks to-day as the most important mctal-niining camp in New Zealand. 
It is situated just within the soutliern limits of the subdivision, and is about six miles 
from the eastern coast-line of the peninsula, and fourteen miles from the river-port 
(Pacroa), wliich gives access to the western seaboard. 

The principal means of communication is afforded by a Government railway, which, 
passing through Waikino and Karangahake, connects Waihi, through Paeroa Junction, 
with the agricultural and colhery districts of the Waikato, and with the provincial city, 
Auckland. 

As the historical section of this report (see page 9) will show, the earhest gold- 
discoveries at Waihi were made in 1878 ; but not until 1894, when the ore w'as found 
amenable to the cyanide process, was marked progress made. 

The production of the camp until the end of 1910, according to available statistics, 
is valued at £9,649,345, and dividends totalhng £4,270,773 have been paid. 

The premier mine, the Waihi, has accoimted for over 95 per cent, of this production. 
All the other claims, owing to the geological structure of the area, are relatively deep- 
level properties, and their development has proved slow and costly. The Waihi Grand 
Junction Mine has. however, been a regular producer since 1906, and the operations 
of the year just closed (1910) have placed the proprietary company in the list of 
dividend-payers. The Waihi Extended and Waihi Reefs Consolidated claims are still 
in the prospecting stage, and have afforded no ore; wliile several areas are held .pending 
developments in the claims now being worked, or the introduction of cajjital for their 
exploration. 

Topography. 

The topography of the Waihi Goldtield differs considerably from that of all other 
fields in Hauraki. The camp is situated on the northern margin of a plain, measuring 
about seven by four miles and a half, wliich is practically surrounded by hills. Tliis 
plain, which hes mostly to the south of the area under review, presents a nearly flat 
or only gently undulating surface, and stands from 250 ft. to 400 ft. above sea-level. 
In its natural state it is covered with only a sparse stunted gro\rth of fern and ti-tree. 

Connected by a small ridge with the lower slopes of the forested range which bounds 
the plain to the northward is Martha Hill, having a local reUcf on three sides of about 
250 ft. Sixty chains to the south-east of Martha Hill, a cluster of hills — the Union, 
Rosemont, and Silverton — rises from the plain to heights of from 200 ft. to 300 ft. ; 
and this area is touched on its south-east side by the steep dyke-hke mass of Black 
Hill, which attains an elevation of 739 ft. above sea-level. 

The Ohinemuri River, the main drainage-channel, meandering across the plain, 
receives the waters of the various creeks flowing from the hilly country. This river, 
making a marked horse-shoe bend around Black Hill, runs close to Waihi Town, and 
from there flows down past Waikino and on through Karangahake Gorge to join the 
Thames River, which discharges to the western seaboard. 

The Town of Waihi covers a considerable area of the relatively fiat country 
skirting Martha Hill upon three sides. 

Geology. 

A description of the mines and prospects of the Waihi Goldfield involves consideration 
of its saUent geological features. Prominence is here given only to such features as have 
a direct bearing upon mining development, other questions of geological interest having 
been discussed in previous chapters. 



124 

The oldest rocks which can be inferred to exist in the Waihi Goldfield are the 
argillites and grauwackes of Jurassic and pre-Jurassic age, which form the basement 
of the whole Hauraki Peninsula. These rocks, so far as the writers know, neither 
outcrop nor appear in mine-workings within a radius of twenty-seven miles of Waihi. 
They may here, therefore, be regarded as comparatively deep seated, and are altogether 
unhkely to be reached in underground exploration.* 

With the exception of gravels, clays, and wind-blown or loess deposits at the surface, 
and certain loosely compacted conglomerates underlying the rhyolites (and probably 
representing old lake-bottoms). Tertiary volcanics form the whole of the superposed rock- 
complex. These volcanics admit of subdivision as follows : (a) Dacites (auriferous scries) 
— "First Period" volcanics; (b) andesites — "Second Period" volcanics; (c) rhyolites — 
" Third Period " volcanics ; (d) andesitic rocks — intrusives, of doubtful age. 

(a.) Dacites (" First Period " Volcanics). — The oldest rocks visible in the area, and 
those of prime economic importance, in that they constitute the auriferous series, are 
pyroxene dacites. These dacites have but a limited development at the existing surface. 
They outcrop in only two small areas, which together measure about 320 acres. 
The more important outcrop forms the well-known Martha Hill, whilst the second 
outcrop forms the Union-Rosemont-Silverton hills. 

Martha Hill is wrapped round on the east and south by rhyohtes, and on the north 
and west by the younger andesites. The Union-Rosemont-Silverton liills area is wholly 
surrounded by rhyohte, excepting Avhere it is touched on its south-east boimdary by the 
dyke-like mass of columnar andesite forming Black Hill. These two inliers of the vein- 
bearing dacites have therefore been described as " islands in a sea of rhyohtes and unaltered 
andesites." 

At a depth of about 950 ft. below the plains, mining exploration has proved that the 
area covered by the dacites is not less than 600 acres, and it may be considerably more. 
As greater depth is attained a much more extensive development of these rocks may be 
anticipated. 

The correct classification of these older volcanics (see pages 11-42) has given rise to 
considerable discussion, on account of the orthoclastic feldspars which these rocks contain. 
Since in all other respects they are normal quartz-bearing andesites or dacites, and as it is 
probable that most of the orthoclastic constituent is secondary (valencianite), the writers 
have classed them as dacites. 

As in all the Hauraki vein-bearing areas, hydrothermal alteration (propyhtization) 
has profoundly affected these old dacites ; and even specimens of dark colour, which 
appear to the casual observer fairly fresh, prove when examined microscopically to be 
considerably altered. 

The structure of tliis altered dacitic complex has presented a problem of great 
difficulty, and one -which, if correctly solved, is of considerable importance from the 
point of view of mining development. An examination of all the accessible mine- 
workings penetrating these dacites revealed only massive or flow rocks. Friction breccias 
occur in connection with certain planes of movement, but no original fragmentals w'ere 
observed. The absence of beds of breccia which might have afforded somewhat definite 
horizons, the similarity both in the physical character and the chemical composition of 
the various rocks existing, and the widespread hydrothermal alteration (propyhtization) 
which has affected the whole complex and masked original characteristics, has rendered 



* The writers were informed that argilUtes were to be to be found on the old track between Katikati and 
Wairongomai, near where it attains its highest elevation. A rough reconnaissance of the locaUty was made, 
but no signs of these rocks were observed. It has also been stated that a borehole in the Woodstock section 
of the TaHsman Mine, Karangahake, bottomed on " slates "' at a depth of over 1,100 ft. below sea-level, but 
the writers have not been able to confirm this. 



125 

the dominant struitunil features obscure. Tl;e weight oi evidence has led the writers 
to the conclusion that a fairly large boss of dacite of rather irregular shape has intruded an 
earlier-fonned complex of rudely bedded dacitic lava-flows. The intetmittent accumulation 
of these flows under surface (subaerial) conditions is indicated by the occurrence, in 
places, of partings and irregular lenses of carbonaceous shaly material. The intimate 
genetic connection of ore-deposits with intrusive rocks the world over is noteworthy, 
and it is probable that the whole of the vein-formation and ore-deposition at Waihi 
owes its origin to the existence of this dacitic intrusion. 

The fixing, as far as possible, of the actual boundaries of the intrusion (and its 
apophyses or offshoots) throughout the field is a work of considerable economic import- 
ance, but one which called for more time than the writers had at their disposal, and 
should therefore be undertaken conjointly by the several mining companies concerned. 
The plans and sections, however, together with the detailed description of the vein- 
fissuring throughout the field, and of the conditions prevailing in each mine, indicate 
the approximate boundaries of the intrusive dacite (the " productive " dacite) and the 
intruded or bedded dacites (the "inferior" dacites). 

(b.) Andesites {" Second Period" Volcanics). — The volcanics of the "Second Period" 
underhe to an unknown lateral extent the rhyohtes of the plain, and form the wooded 
hills rising from the plain to the north and west of Waihi. They also form the floor 
of the relatively open valley lying to the west of Martha Hill. These rocks consist 
in general of hard bluish or greenish black pyroxene- andesites, containing in places 
sparsely distributed small blebs of quartz, but hardly sufficient to warrant the rocks 
being classed as dacites. Breccias and tuffs occur in tliis series, but in very minor 
quantity compared with the flow rocks. With the exception of a small patch on the 
top of a hill 110 chains north-west of Martha Hill, breccias are only observable in 
certain workings of the Grand Junction Mine at or near the contact of these " Second 
Period " rocks with the older dacites. 

The andesites, apart from decomposition effected by surface-waters, exhibit little 
advanced propylitization, excepting near their contact with vein-bearing rocks. In the 
lower parts of the flows in the Grand Junction and Waihi Extended mines, and also 
on the northern side of Martha Hill, alteration is in places pronounced, and renders 
the fixing of the contact between these rocks and the older dacites a difficult matter. 

These " Second Period " andesites appear to be devoid of quartz veins, if certain 
aihceous sinter- deposits occurring some distance from Waihi, and referable to the 
hydrothermal activity which accompanied or followed the extrusion of the overlying 
rhyohtes, be excepted. 

(c.) The Rhyolites ("Third Period'' Volcanics). — The rhyolitic rocks, which are 
probably Pliocene in age, fonn the plain extending east, south, and west of Waihi 
Town. They also form bare scarred hills, rising hero and there from the plain. 

At least three distinct types of rhyolitic lavas occur. In ascending order, these are 
as follows: (1) wSpherulitic pinkish-grey biotite - rhyolite ; (2) brecciated flow rhyohte, 
containing much pumice, pitchstone, andesitic lapilh, &c. (locally known as "wilsonite") ; 
(3) compact light-grey tridymite-bearing rhyohte. 

Each of these varieties — (1) forming the hilly countrj-, (2) and (3) the flow rocks of 
the plain— possesses features of considerable geological interest ; but none of them is 
vein-bearing in the vicinity of Waihi. Auriferous-quartz veins occur, however, in the 
spheruhtic rhyohte at Waihi Beach, some six miles away. 

(d.) Andesitic Rocks of Doubtful Age. — Under this heading falls the andesite forming 
Black Hill. 



126 

There is little reason to doubt that Black Hill is a dyke rock penetrating the 
" First Period " dacites, but whether or not it intrudes the rhyolitic flows of the 
plains, or is merely overlain by them, is an open question. The rock is a glassy 
(hyalopilitic) hornblende - andesite, containing pyroxenes and a little biotite. In places, 
and particularly around its base — namely, near the walls of the dyke — it has developed, 
upon cooling, a well-marked columnar structure. 

Small outcrops of homblende-andesite, not iinlike the Black Hill rock, occur on 
the plain in one or two locaUties, but these are distant over a mile and a half from 
Waihi. Their relationship to the rhyohtes is obscure. 

Detailed Structure. 

Having briefly described the general distribution and relationship of the various 
members that comprise the rock-complex at Waihi, a more detailed description of the 
structure of the mining portion of the field is necessary. Several sectional plans 
have been prepared, both parallel and transverse to the general trend of the reef- 
system, and these will materially assist in ampUfying the descriptions. Unfortunately, 
the workings of the Union-Rosemont-Silverton hills section are not now accessible, and, 
beyond the usual data which figure in mining reports, little information respecting this 
portion of the field is available. 

It will be recognized from the plans and foregoing descriptions that, apart from the 
Martha Hill and the Uuion-Silverton hills, Waihi is a buried goldfield. Prior to the 
extrusion of the younger andesites. there existed an old land, consisting of dacitic rocks, 
these rocks containing the veins of the Martha system. It presented a topography 
similar to that existing to-day in many parts of the peninsula — steep-sided hills, outrunning 
spurs, and more or less deeply incised valleys. This old land, which supported a 
vegetation, stood at least 450 ft., and probably over 800 ft., higher than it does to-day. 
This is deduced from the presence of carbonaceous material near the base of the 
yoimger or " Second Period " andesites in the Grand Junction Mine, 250 ft. below 
sea-level, and from the existence of valleys of erosion at still greater depths. The 
Martha and the Union-Silverton hills, wliich at that time possessed considerable local 
rehef, were coimected by a low saddle-shaped ridge ; and from Martha Hill a long 
outrunning spur struck ofE in an east-north-east direction on the present hne connecting 
the Waihi No. 6 and the Waihi Extended shafts. The eastern flanks of Martha Hill 
itself had a slope-angle approximating 35°. The western and south-western flanks 
were apparently steeper, as judged by the abrupt truncation of the reefs in this 
direction, and by data afforded by boring. The Waihi South borehole, sunk 35 chains 
south-west of the present base of Martha Hill, was reported to have been penetrating the 
overlying younger andesite when abandoned at a depth of 1,500 ft. 

As to how far this ancient topography was due to original volcanic accummulation 
or to agencies of erosion, it is difficult to estimate. It would appear, however, that 
the coimtry comprising the dacitic boss and its environment had been considerably 
affected by erosion between the time of intrusion and the period of vein-formation. 
Subsequent to the formation of the veins, erosion of the dacites was evidently not 
extensive, as the apices of many of the veins were not exposed. These particular veins are 
" bUnd," or feather out in the enclosing dacites. The main Martha lode, however, 
outcropped strongly on the existing surface of Martha Hill. Further eastward, where 
not outcropping, it was found at the upper levels of both the Waihi and Grand Junction 
mines to be, in places, separated from the younger andesites only by a heavy hanging- 
wall band of pug and crushed rock. It is probable, therefore, that erosion had, in 
places, laid bare the hanging-wall of this reef on its trend along the now buried 
east-north-east spur. As an analogous case, it may be mentioned that the Tokatea 



127 

big reef at Coromaiidel presents an exposed hanging-wall for some distanee on the steep 
western side of Tokatea Kange. The apices of the Empire and the Koyal lodes were 
not exposed, excepting on both the eastern and western flanks of Martha Hill. It 
is reported that the veins here showed evidences of feathering-out on approaching the 
old hillsides. 

Mining operations have not revealed the nature of the topography of the old 
dacitic land north of the Martha lode. At the No. 8 (850 ft.) level. Waihi Mine, a 
horizontal bore (725 ft. in length) projected from the Trout crosscut was reported to 
have been penetrating the dacites when abandoned at a point about 11 chains from the 
foot-wall of the Martha lode. 

The vein-bearing country just described was subsequently flooded with andesitic 
lavas of the " Second Period." The main foci of eruption were probably situated to 
the northward and westward of the mines ; and the extrusion of lava was preceded 
by Ught showers of ash, which have afforded the thin bands of tuffs and breccias found 
here and there at the base of these yoimger andesites. The sectional plans, constructed 
on various lines throughout the area, show the disposition and extent of these rocks 
as far as is known. 

The more steeply dipping contacts between these andesites and the older land-surface 
— the dacites — are usually marked by a heavy band of slickensided pug. This puggy 
band, which was in the earlier years of mining development mistaken for a fault, 
follows the circuitous contour of the old buried flanks of Martha Hill. Again, as already 
remarked, it follows the hanging-wall of the Martha lode where this lode was exposed on 
the steep southern slope of the east-north-easterly trending spur. When followed 
downAvard this puggy band departs gradually from the hanging-wall of the lode, and 
probably gives out where it merges into the flatter-ljang basal contact of the two rock- 
series. The belt of puggy material is probably due in part to decomposition of the rock by 
seeping waters, and in part to movements of subsidence in the younger andesite attend- 
ing contraction on cooling. It is doubtful as to whether or not these younger andesites 
ever completely covered Martha Hill, or as to what extent the valleys excavated in these 
flows are due to the agencies of erosion. 

Between these andesites and the overlying rhyolitos in the Waihi Consolidated shaft, 
at from 390 ft. to 410 ft., and elsewhere at depths of from 100 ft. to 500 ft. below the 
present surface, heavy loosely compacted conglomerates have been penetrated. These are 
fluviatile boulder-gravels, deposited CA-idently by the high-grade tributaries of the ancient 
Ohinemuri. 

The rhyohtic eruptions of the Pliocene period flooded this old valley of the Ohine- 
muri. The earliest extrusions of the viscous spherulitic rhyolite appear to have ponded 
the river, and subsequently reversed its drainage from the east coast to the west coast. 
The old valley-basin was subsequently filled by the later rhyolitic lava-streams. The 
whole topography of the region was thus altered, and a relatively extensive plain, with 
arms stretching up the lower reaches of valleys excavated in the andesites, replaced the 
more diversified land-forms. 

The mining engineer is concerned with these younger andesites and rhyoUtes only 
in respect to the depth at which they overhe at any particular point the old dacitic 
auriferous series. From the descriptions and sectional maps it will be readily recognized 
that the vein-bearing dacites exist in great part as a buried land of very irregular 
configuration. Thus, apart from the extension of crosscuts and drifts from the present 
mine-workings, only the actual penetration of the rock-mass by boring or shaft-sinking 
can detennine at any given outlj-ing point the depth of the overburden. The engineer 
is here further confronted with the possibiUty that the younger andesites, or the 
rhyolites in certain localities, are intrusive, or fill crateral vents, a condition which 



128 

would preclude the existence of the vein-bearing rock in these particular localities. It 
seems certain that the andesitic mass forming Black Hill, which abuts on the south side 
of the Roscmont-Silverton hills portion of the Waihi Claim, and on the Waihi-Oladstoih' 
Claim, is intrusive. Some of the other andesite liills and ridges which rise boldly from 
the plains on the eastern strike of the Martha vein-system may also be in part intrusive, 
although no precise indication of localities of intrusion can be given. The same remarks 
a])ply to the wooded hilly andesite country lying to the north and west of Martha Hill. 
Tile conduits of the rhyolitic eruptions are as obscured as those of the andesites. Some 
of these are e\ndently not far distant ; in fact, the younge.st rhyoUte is. at several points 
in the neighbourhood of Waihi, found breaking through one of the older rhyohtes 
(wilsonite). 

Vein-system. 

A very complex series of conjugate fissure-veins comprises the Martha vein-system, 
and has afforded the whole of the ore of this goldfield. The sum total of the proven 
vein-bearing area, as already stated, is about 600 acres, and on the strike of the vein- 
system quartz is traceable over a length of 89 chains. 

The strongest lode, and that which has proved the principal ore-producer, is the 
Martha, the outcrop of wh'ch has been removed in a large opencut on Martha Hill. 
Its average strike is N. 57° E.. and its dip is to the south-eastward at angles approxi- 
mating 80°. Underground it has a proven extension of 5.100 ft. At the outcrop the 
width of the lode ranged from 5 ft. to 50 ft. ; lower down, where several hanging-wall 
branches junction with it. widths up to 12') ft. were reported. At the 1.000 ft. level 
(No. 9, Waihi; No. 5, Grand Junction) this lode has an average width of 50ft. over a 
proven length of 3.050 ft.* 

The Empire lode and the Royal lode are, next to the Martha, the two most 
important and persistent veins of the system. 

The Empire, which reached the surface of the enclosing dacites only in the buried 
eroded flanks of Martha Hill, has in the Waihi and Grand Junction properties together 
been followed for 3,0.50 ft. at the 1,000 ft. level, and for lesser di-stances, depending upon 
the old contours, at shallower horizons. In the main, this lode strikes parallel with the 
Martha, and dips towards it. and is in reality a hanging-wall branch which will junction 
with the parent lode at horizons deeper than those yet explored. At the 1,000 ft. level 
the average width of this lode is 27 ft. 

The Royal, which lies still further from the Martha in the hanging-wall country, and 
presents a general parallehsm to the Martha and Empire, has a proven longitudinal 
extension of 3,600 ft. Like the Empire, it dips towards the Martha at high angles, and 
should also have a deep-seated junction with the parent vein. This lode, where travers- 
ing the old Martha Hill, probably persists up to the, buried surface of the dacites, but 
elsewhere feathers out in these rocks. Its average width at the 1.000 ft. level is about 
22 ft., with, on the whole, gradually diminishing strength from here upward. 

The Edward lode, which is confined to the more westerly portion of the Waihi 
Mine, and is now one of the most important producers, had its apex at a depth of 
■100 ft. below the surface of the enclosing dacites. It here appeared as a separate vein 
connecting the Welcome, a hanging-wall branch of the Martha, with the Empire and the 
Royal. At the 1,000 ft. level, however, the Martha-Welcome-Edward is one single 
continuous vein with a crescent-like trend, and undoubtedly represents the western or 
south-western portion of the major fissure of the system. The Edward shows in marked 
degree — at least, to the 850 ft. level — the inverted wedge-shaped cross-section. At the 
horizon named the wider cross-sections measured from 75 ft. to 90 ft. At the 1,000 ft. 



* This does not include the Weloome and the Edward, which at the 1,000 ft. level are in reality the 
westerly or south-westerly extensions of the .Martha. 



jh aciomnanv JBvdljufin, [N° /.5 



JAM£5 MACKINTOS 



WA LEVEL, 

(353 feet down N?l Shaft) 

Showing geological formation, principa 
and mine workings 





ini'i i 



Scale of Feet 




*» *«(»cwn JoMi liaem:i. Utatntmm ftiittw. 



yoo- T.iz^eaB 






'"'*w ,j3v:' 



\ 






:v^.- 



a aca>mpajty BuUrXin. Jf" IS.WaiMTaatui Suhdlrisiarv Hcaa-aJ^IKyiiiuiiv. AxtdtUintl, ZanA BUtiUt 



PLAN 

Showing the Geological formation, veins, faults, and 
principal workings throughout the deepest existing levels of the 

WAIHl GOLDFIELD 

viz.- N? 9 Level, Waihi Mine, 1003 ft below the surface 
N9 5 » Waihi G Junction Mine . 944 ft do 
N? 5 , Waihi Extended . 960 ft do. 

Shows also the lines along which vertical sections have been constructed. 



Waihi Extended CM C? 




By /{WJwnVj', J^]%n Matha^ 



d ■: I ■*• 






IHIAW' J 



-^3g»fe-, 



129 

level the width throughout the 700 ft. so far exploited averaged 30 ft. Th's lode is 
disposed nearly vertically, or with a slight dip to the eastward. 

In addition to the principal veins mentioned, the plans show the subsidiary veins 
proved to exist at the 1,000 ft. level — namely, in the Waihi Mine, the Alexandra, a 
hanging- wall loop of the Empire; and the Rex, a branch of the Royal: in tiie Grand 
Junction, the No. 2 and Mary lodes, foot-wall l)ranches of the Martha ; and the Grace 
lode, a hanging-wall branch of the Martha ; also the George lode, a loop of the Royal ; 
and other smaller and less important members. 

In contrast to the comparatively few subsidiary veins in the Waihi Mine at the 
1,000 ft. level is the great number of veins, many of them strong oro-bodies, which were 
found to exist at shallower levels. Those which have proved the stronger and more 
important are known as the Welcome, Regina, and Magazine, hanging-wall branches of 
the Martha, all disposed at higher angles than the parent lode, and usually making with 
it south- westerly pitching junctions. Of less importance were the No. 2 lode, a branch 
striking off the foot-wall of the Martha and running approximately parallel with it ; 
the Victoria and Surprise veins, which occurred within the wedge-shaped " horse " of 
country separating the Welcome from the Martha ; the Albert, a spur vein running 
north-eastward from the Empire towards the Martha; the"H,""I." "J," " K," " L," 
and Princess, spur veins striking south-westward from the Empire, and persisting only 
short distances ; the north branch of the Royal, connecting the latter with the Empire ; 
and the Rex, a south-westerly branch of the Royal. 

In the Union -Silverton section of the Waihi Mine, where the principal workings 
extend to a depth of 450 ft., occur several veins which formerly yielded ore. The 
stronger of these are the Union, Mascotte, and Amaranth, confonning in general trend 
with the prevailing strike of the Martha Hill -Grand Junction veins, and the Silverton 
vein, lying further to the eastward, and striking almost transversely to the other three. 

In the adjoining Waihi -Gladstone Claim two or three veins parallel to the Union and 
Amaranth exist, and one of these has given, from shallow workings, a small tonnage 
of ore. 

The maps and sections will show the relative positions and the relationship of the 
various veins. No workings yet connect the Martha section with the Union-Silverton 
section of the Waihi Mine; but, whether the veins of these sections prove to be directly 
connected or not, the whole of them, as will be mentioned later, are, on the score of 
genesis, considered to belong to the same system. 

Origin oj the Vein Fissureti. 

The outstanding feature of the Waihi vein-system is the large nimiber of veins which 
exist, particularly in the Martha Hill -Waihi Grand Junction portion of the area. Thie 
feature, having regard also to the trend and disposition of the various veins, impUes 
a very compUcated fracturing and fissuring of the enclosing rock-mass. It has also 
been pointed out that the prevailing trend of the vein fissures deviates about 35° from 
that of the general direction of vein-fissuring throughout Hauraki. 

At Waihi the fissuring which has determined the position of the veins is, as might 
be inferred, of local origin, and exhibits a close relationship to the geological structure 
of the enclosing rock-mass. The theory has been advanced by the writers concerning 
the vein-bearing rocks at Waihi that a boss of dacite, designated the " intruflive dacite," 
has been intruded into irregularly bedded dacites. The shape of this intrusive is, in 
plan, roughly that of an elUpse, with an area diminishing at first fairly rapidly and 
subsequently more gradually as followed downwards. At the 1,000 ft. level it measures 
about 50 by 20 chains. The shattering and fissuring of this intrusive dacite, which 
encloses the more productive veins, and of the intruded dacites, which also carry veins, 
9— Waihi-Tairua. 



130 

were evidently the result of a severe shock. This was probably of the nature of an 
earthquake, and occurred while the intrusive dacite was in a state of tension. The main 
lines of fissuring — the Martha, Empire, and Royal — were developed mainly within the 
dacite intrusive, and in directions approximately parallel to its major horizontal axis. 

The Martha fissure in the upper levels of the Waihi and Grand Junction claims 
appears to lie altogether within the northern border of the intrusive dacite, but at lower 
levels it is found at or near the contact of this rock with the intruded dacites. The 
Empire lode follows approximately the major axis of the intrusive. The Royal lode 
occupies a structural position somewhat analogous to the Martha, since it occurs within 
the intrusive and near the southern boundary of the same. 

Where followed westward in Martha Hill a decided weakening, or a termination of 
the fissuring, is evidenced. At the upper horizons the lode here designated the Martha 
sphts up into numerous parallel stringers. The main hne of fracture here is the 
hanging-wall branch, the Welcome, which is traceable to and beyond the " B " shaft of the 
Grand Junction Company's western property. At lower horizons both the Martha and 
Welcome veins westward of Waihi No. 2 shaft become weaker and weaker as followed 
downward, until at No. 8 (850 ft.) and No. 9 (1,000 ft.) levels the main hne of fissuring 
has been found to deviate from the westerly direction followed at upper horizons and 
pursue a southerly course. Thus there exists here that portion of the lode known as the 
Martha-Welcome-Edward, with its pecuUar crescent-shaped trend. The southern end of 
the Edward, moreover, junctions with the Royal, which here bends somewhat towards 
the northward. Tlie Empire lode, intermediate between the Martha and Royal, strikes 
the eastern wall of the Edward about normally, and here terminates. 

The continuous Martha-Edward Une of vein fissure, together with the Royal, is, in 
plan, disposed as the end of a roughly elhptically shaped area. On the 850 ft. level, 
what is designated the Royal lode, west of the Edward junction, is really the extension 
of the Martha-Welcome-Edward, the parent fissure. This should become more evident 
at deeper horizons. 

The pecuhar behaviour of the fissures just described is solely dependent upon the 
structure of the enclosing rock-mass. Within this end of the elhptically shaped area 
enclosed by the veins at the deeper levels is the intrusive dacite, outside is mainly the 
bedded or "inferior" dacites; in other words, these portions of the veins structurally 
partake of the nature of contact deposits. 

In the shallower horizons of the Martha Hill section the intrusive dacite appears to 
have extended further to the westward in rather mushroom-hke fashion, and the fissure- 
veins also extended westward with it. Apparently the shock which propagated the 
fissures had a greater effect on the intrusive dacite than on the less homogeneous bedded 
complex which surromids it. 

Passing to the opposite end of the field, developmental work in the Grand Junction and 
Waihi Extended has shown that with the exception of the Martha lode all the veins 
show marked evidences of weakening in the more easterly workings. As the following 
pages will indicate, this appUes to both the Royal and Empire lodes and to the No. 2 
lode of the Grand Junction and Waihi Extended claims. Irregular bands of veinstone, 
many of these striking obUquely to the general trend of the system, are making their 
appearance, hkewise cross-courses, sheeted faults, and disturbed country. Examination of 
the rock in the workings here was rendered difficult owing to poor ventilation-conditions. 
The structure is evidently very comphcated. Irregular areas of bedded (" inferior ") 
dacites were observed to exist, so that it is highly probable that the eastern hmits of 
the intrusive dacitic boss are here being reached. 

The veins of the Union-Silverton section occur altogether in the bedded dacites, and 
the fissuring here is an expression of the same shock as that which formed the fissures 



131 




9 •— Waihi-Tairua. 



132 

in the intrusive dacite. The trend of the most easterly vein — the Silverton — is significant, 
and suggests that, as in the western part of the Waihi Claim, so in the Waihi Consoh- 
dated and eastern portion of the Grand Junction, a bending or lapping around of vein 
fissures beyond the eastern limits of the dacitc-boss may be expected. 

Much of the veinstone at Waihi has been deposited in open spaces. In both the 
Martha Hill section and in the Grand Junction the inverted wedge-shape of many of the 
veins, as well as the feathering-out at the original apices, is indicative of the fractures 
having been widened at the lower horizons. The veins of the Union-Silverton section, 
on the other hand, have, as far as developed, shown a marked decrease in width as 
followed downwards. Such conditions are explainable on the theory that a relatively 
local depression or subsidence of the country took place, the centre of depression being 
with n the dacite -boss. Such a movement would have a tendency to widen the 
fissures at lower horizons and to close them near the surface — that is, within, and 
especially towards the centre of, the intrusive mass. In the bedded or "inferior" 
dacites, the locus of the Union, Silverton, and Amaranth veins, the tendency would be 
to open the fissures near the surface and to close them below. 

Within the much-fissured Martha Hill section the compression tending to close the 
fissures near the surface helps to explain how huge masses of rock cut ofi by subsidiary 
fissures were supported. The support afforded these cut-off blocks by shoulders or 
irregularities on the walls would hardly seem to have sufficed in the case of these 
particular veins. 

Evidences of movement and brecciation are to be foimd in many places throughout 
the vein-system. At the same time, it would appear that little faulting accompanied 
the formation of the fissures. That very minor differential movement along a vein 
fissure may produce smooth sUckensided walls and brecciation of country is conclusively 
shown in connection with the No. 2 lode, a foot-wall branch of the Martha in the Waihi 
Mine. This lode, which exhibits the evidences of movement stated, intersects, at the 
No. 7 (704 ft.) level, a flat-lying carbonaceous band in the bedded dacites. This band 
is clearly traceable on both walls of the vein, and shows no appreciable displacement. 
If this band, or others which exist, could be traced on each side of the Martha lode 
itself, data as to faulting along the main fissure would be afforded. On the hanging- 
wall side of the Martha, however, the intrusive dacite alone appears to exist. 

The longitudinal extension of fissures gives, as a rule, some indication of their 
extension in depth. The Martha-Edward vein fissure at the 1,000 ft. level exceeds 
5,000 ft. in length,^ while the Empire and Royal measure over 3,000 ft. and 3,600 ft. 
respectively. The first-named might be expected to persist through a vertical range 
exceeding 2,500 ft., above which horizon both the Empire and Royal will have terminated 
on its hanging-wall. The veins within the surroimding " inferior " dacites, for reasons 
already stated, can hardly be expected to have great persistence in depth. 

Sequence of Mineral Deposition in the Veins. 

The Waihi veinstone is the product of at least three different impregnations by 
mineral-bearing hydrothermal solutions. These, in order of occurrence in time, are as 
follows : (a) Impregnation resulting in the deposition of carbonates, mainly manganiferous 
calcite ; (6) impregnation resulting mainly in the deposition of quartz and the various 
ore minerals (sulphides, gold and silver, &c.) ; (c) impregnation of minor degree compared 
with (a) and (6), resulting in the deposition of gold-silver-bearing sulphides with some 
quartz, carbonates, &c. Changes have been effected in the veinstone, particularly in 
that of the upper horizons, by waters migrating from the surface, but these are more 
conveniently considered separately. 



133 



(a.) In the fissures the earliest veinstone deposited was calcite, containing usually a 
small percentage of manganese. The genesis of the Waihi veins is in tliis respect 
identical with that of the veins of the not-far- distant Maratoto, Komata, and Golden 
Cross fields. Speculations as to the origin of these carbonate-bearing waters, wliich 
so abundantly manifested themselves throughout the particular area enclosing these 
fields, are discussed in another part of this report (page 53). At Waihi the calcite was 
deposited mainly in the open spaces which the fissures presented, and consequently tliis 
mineral and its subsequent replacements show httle or no evidence of stress phenomena. 
The theory that the fissures were gradually widened by forces attributable to crystalhzation 
may also, to a great extent, be discounted. 

The carbonate is usually white, but where the manganese-content increases pinkish 
tints are noticeable. The rhombohedral cleavage is usually well marked. The percentage 
of magnesia present is invariably low. The foUowng are analyses of three samples of this 
primary vein-filhng, but in two of them the replacement by sihca was more advanced 
than was recognized when the specimens were collected : — 



8ilica (SiOj) . . 

Iron-oxide and ulununa (Feo03 AI^O.,) 

Manganese-oxide (MnO) 

Lime (CaO) 

Magnesia (MgO) 

Carbonic anhydride (COg) 

Moisture and orj^anic matter (CO^) 



liK)(K) 100-00 10000 

Gold-content : No. 1, 1 gr. per ton ; No. 2, 0-5 gr. per ton ; No. 3, nil. 
LocaUties : No. 1, Empire lode. No. 5 level, Waihi Grand Junction Mine ; No. 2, 
Martha lode, No. 9 level, Waihi Mine ; No. 3, Martha lode. No. 5 level, Waihi 
Grand Junction Mine. 
In the lower levels of the Grand Junction Mine, especially where the veins carry 
no ore — for example, along certain stretches of the Martha lode at No. 5 level — calcite 
showing comparatively httle replacement extends from wall to wall, widths of 50 ft. 
or 60 ft. being not uncommon. Similar cross-sections are also ol)servable in many 
places in the Waihi ^Lne. Again, throughout the whole vein-system, both associated 
with the ores and with impayable veinstone, Inuiches and bands of calcite, and t!ie 
huge amount of quartz which is unmistakably pseudomoi^phous after tliis mineral, testifies 
to the fact that the carbonate constituted at all horizons the original vein-filhng. 



(1.) 

Per Cent 


(2.) 
Per Cent. 


(3.) 
Per Cent. 


0-65 


12-10 


17-40 


0-40 


0-10 


0-15 


3-20 


1-88 


1-78 


53-35 


47-58 


44-50 


0-15 


0-25 


0-15 


42-25 


37-70 


35-58 




0-39 


0-44 



hoot-waJi country 



■a . . V . 






<^ • 



■ £.j_' 4 --i-S— :!__ Xj a . V ■. /\- ■ 7— . . c ■ "^^ Sulphide ore 

'^''uggy selvage 



L'^- 'J- I -J -I 'I t- -1-^1 



-/-/ / 



Calcite with some 



■ I — / / / -/- / ' \ Cjuartzose replacement 



Hanging-wall country 



Sketch-plan of a veey common Disposition of the Veinstone in both the Waihi and the Waihi 
Grand Junction Lodes at the Deeper Horizons. 



134 

(6.) The second and, ccouomicixUy, the most important phase of vein-fonnation — the 
I'ise of sihceous metal-bearing solutions — appears to have been preceded by a reopening of 
the carbonate-filled fissures. This reopening and shattering generally occurred along the 
walls of the veins, particularly the foot-walls, and was attended with a considerable 
amount of brccciation of the wall-rock. A widespread shattering of the carbonate vein- 
tilling was at the same time also effected. The ascending heated solutions deposited their 
burden in open cavities, filling fissures opened in the wall-rock and in the carbonate vein- 
stone. Angular fragments of brecciated wall-rock were encrusted and re-cemented. 
Extensive replacement of the wall-rock by sihca and ore minerals was effected, and 
there ensued on a wholesale scale dissolution of much of the carbonate, and its replace- 
ment by quartz (pseudomorphous quartz). 

The most abundant mineral deposited was, of course, quartz in one form or another ; 
and with this were associated, in places sparsely, again in considerable quantity, metal- 
liferous sulphides. The predominant sulphide is pyrite ; the others of frequent occurrence 
are sphalerite, galena, chalcopyrite, and argentite. The various accessory minerals occurring 
will be mentioned in the more detailed description of the ore. It would appear that 
some calcite and mangano-calcite was also deposited during this stage, but it is difficult 
to differentiate between these carbonates and those of earher generation. 

To this period of vein-formation is referable by far the greater part of the gold- 
silver content of the veinstone, the precipitation of these metals having been intimately 
associated with that of the stilphides. 

(c.) A rejuvenation of ascending mineral-bearing solutions (third impregnation) is 
beheved to have afforded certain bands of high-grade sulphide ore, or certain enriching 
constituents thereof, also veinlets consisting of quartz and calcite, which cut the older 
vein-material. Recognition of such younger ore-bands and ramifying veinlets rests mainly 
upon the sequence of the fracturing and fissuring rather than upon mineralogical 
characteristics. Fracturing prior to the close of the second phase of vein-forming activities 
would have given hke structures ; so also would the filhng of fissures and cracks by 
later descending solutions. Nevertheless, after a close examination of all the lodes it is 
considered that a good deal of evidence exists pointing to a rejuvenation of ascending 
mineral-bearing solutions. 

As supporting the theory of successive rejuvenation of deep-seated ground-water 
activities, certain facts mentioned previously may be recapitulated. The younger andesites 
overljdng vein-bearing dacites are themselves, although non-vein-bearing, considerably altered 
near their basal contacts, and especially in the near vicinity of the veins. Further- 
more, auriferous-quartz reefs occur in the rhyohtic rocks at Waihi Beach, some six miles 
from Waihi, the rocks being even younger than the barren andesites mentioned. 

Nature of the Vetn-materinl. 

The vein-material of the Waihi Goldfield may, for sake of description, be considered 
under the following headings: (I) Sulphide ore; (2) barren or low-grade vein-material; 
(3) oxidized vein-material. 

(1.) It should be stated at the outset that in many cases no hard hne separates what 
is regarded as sulphide ore from barren or low-grade veinstone, and, again, in the Waihi 
Mine there is every gradation from these products to completely oxidized vein-material. 

Generally stated, the sulphide ore consists of a gangue of quartz, manganiferous calcite, 
and minerahzed propyhte, with a variable percentage of sulphides — pyrite, sphalerite, 
galena, chalcopyrite, and argentite — and accessory minerals. In the Waihi Mine the 
sulphides, even in the lowest levels, are reported to amount, on the average, to about 



135 



4 per cent.* of the ore only. In the adjoining Waihi Grand Junction Mine tliey are said to 
constitute from 8 to 10 per cent, of the ore treated.! 

Two varieties of sulphide ore are recognizable — namely, the non-banded and the 
banded ore. 

The non-banded ore consists, in the main, of highly mineraUzed (metasomatically 
replaced) country rock. So pronounced has been the minerahzation that the original 
character of the rock has been completely masked, except in isolated cores or lenses. 
This ore consists mainly of quartz of gre\nsh or greenish-grey colour, and of somewhat 
granular or finely crystalline textures impregnated wth the sulphides. Under the 
microscope it appears as a fine mosaic of granular quartz, with, patches of chloritic or 
serpentinous material, carbonates, and sericite, through the whole of which are dispersed 
sulphides as grains, nests, and tiny veinlets. Occasional pseudomorphs of adularia or 
valencianite, whicli is common in the highly altered wall-rock, also occur in some of this 
ore. Some of the replaced coimtry now forming ore is of a peculiar dark-greenish 
colour, earthy or even puggy in character, and is heavily charged with pyrite. A 
sample from the eastern part of the Royal lode at No. 9 level, Waihi Mine, on assay 
shows an unusually high ratio of gold to silver, namely — Gold, 1 oz. 15dwt. 7 gr. per 
ton ; silver, 1 oz. 8dwt. 23 gr. per ton. The general appearance of tliis ore is, however, 
no criterion as to its value, as a specimen from the same lode at this level, collected 
near the Waihi -Waihi Grand Junction boundary, vnelded — Gold, 2dwt. 12 gr. per ton; 
silver, 3dwt. 18 gr. per ton. A sample of similar ore from the foot-wall sulphide band 
on the Martha reef, above No. 7 level, gave on analysis the following results :- 

Per Cent. 
Sihca (SiO,>) .. .. .. .. .. .. ry.)-5:) 



Alumina (AljO;,) 
Ferric oxide (Fe^O;,) 

Iron-pyrite (Fe.S2) 

Lime (CaO) 

Magnesia (MgO) 

Potash (KjO) 

Soda (Na^O) 

Titanium-dioxide (TiO,,) 

Carbonic anhydride (COj) 

Loss on ignition (excluding S. & (0^) 



7(t2 
4-8(» 
8-3U 
312 
y-7'.t 
068 
0-60 
Nil. 
1 -.30 
510 



l(Mi-26 
Assay — Grold, 17dwt. 15i;r. per ton , silver, 2 oz. 4 dwt. 2 iiv. per ton. 

The gradation from payable vein-material of the replacement type to unprofitable 
wall-rock is, in many places, as might be expected, a gradual one, and in such cases only 
systematic sampUng and assaying determines the economic hrait to which mining proceeds. 

The separation-hne between banded and non-banded ore is not infrequently an 
arbitrar}' one, as filUng of fissures and replacement of wall-rocks proceeded contempo- 
raneously, thus affording transitions from the one variety to the other. Some of the 
banded ore, however, is observed, both on megascopic and microscopic examination, to 
be of subsequent formation to the replacement ore, and may in part belong to what has 
been regarded as the third phase of vein-formation. 



• " Milling and Treatment at the Waihi Mine, N.Z.," by E. G. Banks, Trans. Aust. Inst. Min. Eng.. 
voL 8, 1911. 

t " Metallurgical Process of the Waihi Grand Junction Gold Company, Ltd., N.Z.," by Alexander Fyfe 
Trans. Aust. Inst. Min. Eng., vol. 8, 1911. 



136 



The banded sulphide ore, whicli is usually liigh grade, shows parallel wavy bands, 
consisting almost, entirely of the various sulphides intercalcatcd with others of quartz. 
The latter is compact, often somewhat chalcedonic and white, or tinted greyish or 
bluish by very finely divided sulphides. Occasionally an amethystine tint in the quartz 
indicates the presence of manganese. Under the microscope even the small veins show 
closely set parallel strings of quartz, often banded and comby, alternating with seams 
and strings of pyrite and argentite. Crustification is in places apparent, the median 
partings being Uned with fine drusy quartz. Concentric and nodular forms and crusts 
surrounding included rock-fragments are common. Geodic quartz, showing large crystals, 
is, it may be mentioned, not conspicuous in the Waihi ores. 

The available evidence is indicative of the contemporaneous precipitation of the 
various sulphides, as the order of deposition is never constant. One selected crustitied 
specimen shows the following sequence : (1) Galena and sphalerite, (2) chalcopyiite. 
Another specimen : (1) Galena and sphalerite, (2) pyrite, (3) galena, (4) sphalerite and 
pyrite. Yet another: (1) Pyrite, (2) galena, (3) chalcopyrite. 

In both non-banded and banded sulphide ores the gold occurs mainly in pyrite, and 
to a lesser degree in galena and sphalerite. Even silver, in the sulphide sample experi- 
mented upon, was found to occur in greater quantity in the pyrite than in the galena. 
Undoubtedly, however, the greater bulk of the silver is referable to argentite, which 
mineral occxirs usually in the finely granular form. The gold-silver-bearing pyrite 
possesses a bright steely lustre, the dark " dead-looking " amorphous pyrite being almost 
invariably barren. Sphalerite (zinc-blende) appears in various forms — platy, reniform, 
and fibrous, or massive and either coarsely or finely crystalhne. This mineral is often 
intimately associated with galena. The galena nearly always occurs in finely granular 
condition. Chalcopyrite is not a.^. abmidant as the sulphides mentioned. It is of the 
usual character, and, more particularly in the eastern portion of the field, indicates 
the presence of high-grade ore. 

As showing the chemical compositions of bulk ore, for the most part unoxidized, 
the following figures may be quoted: (1)* An approximate analysis (wet - crushed mill 
sample) of ore mined between the 400 ft. and 850 ft. levels, Waihi Mine ; and (2)t an 
analysis of the iisual grade of mill concentrates (- about 1-5 per cent, of the ore), Waihi 
Mine. 





(1.) Per Cent, 


(2.) 




Per Cent. 


Sihca .. 


. . 90-80 


Sulphur 


. . 35-00 


Alumina 


2-89 


Iron . . 




. 32-43 


Iron-oxide 


. . 0-82 


Copper 




0-05 


Iron -sulphide 


248 


Lead . . 




0-32 


Manganese 


. . 0-43 


Zinc 




2-05 


Lime . . 


0-69 


Arsenic 




. 0-10 


Magnesia 


. . 0-15 


Manganese 




1-02 


Copper) 
Lead 




Lime . . 




. 0-85 


. . Traces. 


Magnesia 




. Traces. 


Zinc ) 




Sihca . . 




. 27-65 


Undetermined 


. . 0-35 


Loss, &c. 




. 0-53 


Loss on ignition 


1-39 








100-00 






100-00 



* " Milling and Treatment at the Waihi Mine, N.Z.," by Banks, E. G., Trans. Aust. Inst. Min. Eng., 
vol. 8, 1911, p. 83. 
t Loc. cit., p. 94. 



137 

The proportion of gold to silver in the whole of the ore mined by the Waihi 
Company in 1910 was 1 : 8-2. In the concentrates from this ore the proportion was 
as 1 : 94. 

Selenium is obtained in refining the Waihi bullion. No definite selenium mineral 
has yet been detected in the ores, biit the results of analyses lead to the conclusion 
that the selenium partially replaces the siilphur of certain sulphides, and it is not 
improbable that selenide of silver and even selenide of gold may be present. 

The occurrence of certain other minerals, or mineral aggregates associated with the 
sulphide ores, is worthy of note. 

The unusual and rather remarkable occurrence of a mass of white or cream-coloured 
soft powder)' material re-cementing angular blocks of wall-rock, and extending for a 
width of 20 ft., was recorded in the intersection of the Empire lode in main crosscut, 
No. 5 level, of the Waihi Grand Junction Mine. This material, although containing 
very Uttle disseminated pyritc, had a relatively high gold-silver content. An analysis 
and an assay of a sample collected are as under : — 

Per Cent. 

Silica (SiO.) .. .. .. .. .. .. 61-23 

Alumina (AL,0., ) 

Ferric oxide (Fc.O.,) 

Manganous oxide (MnO) 

Lime (CaO) 

Magnesia (MgO) 

Potash (K2O) 

Soda (Na^O) 

Titamum-dioxidc (TiO^) 

Carbonic anhydride (CO,) 

Loss on ignition (excluding COg) 



Assay — Gold, 3oz. Ifidwt. 21 gr. per ton 

In the above sample the amount of carbon-dioxide present is just sufficient to 
combine with the lime. The alumina and magnesia are evidently combined as silictates, 
and free siUca is present to the extent of about 50 per cent. 

A white rather waxy-looldng material, which resembles a kaohnite, is of not infrequent 
occurrence as renifomi scales in vugs and cavities, and as filmic intercalated with 
crustified ore. This, as the analysis cited on page 58 indicates, is almost pure silica, and 
is the same as the " sihca " regarded as a good " indicator" in the veins at Thames. 

A white, granular, fairly soft, powdery material, which occurred in considerable 
quantity as a cementing material in high-grade brecciated sulphide ore on the foot-wall 
portion of the Martha, at No. 7 level, Waihi Mine, has the following composition : — 

Per Cent. 













501 












0-30 












0-62 












11-37 












7-57 












0-25 












. 0-24 












Nil. 












8-77 












4-77 








100-13 


; silver, 


1 1 07.. 


Od 


[wt. 


7gr. 


per ton. 



Alumina (AI2O3) 


00-4 

5-22 


Ferric oxide (FcjOj) 


0-72 


Manganous oxide (MnO) 


Nil. 


Lime (CaO) 


Nil. 


Magnesia (MgO) 


2-20 


Alkalies, and loss on ignition . . 


.. 5-10 



100-00 



188 



A pinkish, rather powdery, cementing material is conspicuous in rich brecciated 
sulphide ore in the foot-wali poitiun of the Martha lode at No. 6 level. The analysis, 
restated, is as follows : — 



SiUca (SiOa) 


Per Cent. 
. . 55-60 


Alumina (AI2O3) 


1-U7 


Ferric oxide (FejOg) 


0-63 


Manganese-carbonate (MnCOg) 


. . 37-38 


Calcium-carbonate (CaCOg) 


3-21 


Magnesium-carbonate (MtjCOg) 


1-70 


Undetermined 


0-41 



100-00 

(2.) The barren or low-grade veinstone (uiioxidized) consists principally of nian- 
ganiferous calcite and quartz, with .sheeted or brecciated wall-rock in various stages of 
silicification. Small sporadic patches of sulphides, mainly pyrite, are in places not 
uncommon, there being every gradation from low-grade veinstone to ore. 

The calcite is a co mm on constituent of this class of vein-filling in all the mines, 
and, on the whole, shows a progressive increase Avith depth. Its physical character 
and chemical composition has already been indicated. The quartz is both the pro- 
duct of fissure-filling and tlie replacement of calcite and wall-rock. The pseudo- 
morphous type is the most abundant, and exhibits the usual cellular, platy, and 
hackly structuies. White saccharoidal or sugary quartz, resembling a grit or sand, 
evidently represents friable pseudomorphous quartz crushed by movements along the 
veins. A sample of this white sugary variety un analysis gave the following results : — 



Silica (SiOj) 
Alumina (AI2O3) 
Lime (CaO) 
Magnesia (MgO) 
Loss on ignition 



Per Cent. 
98- 15 

1-27 

Nil. 

0-21 

0-37 



100-00 
Gold-content, 0"5 gr. per ton. 

Several other varieties of quartz are present, varying from coarsely crystalline to 
flinty and chalcedonic. On the whole, the finely crystalline or chalcedonic types pre- 
dominate. Banded or wavy structures in the chalcedonic and flinty quartz are not 
uncommon, but these are moi-e frequently associated with the quartz of the pay-ore. 
A white, exceedingly fine-grained quartz, almost resembling alabaster, is a curious 
form. Much of it, however, on microscopic examination proves to be pseudomorphous 
after calcite. The smaU sporadic patches carrying sulphides usually occur in the 
vicinity of the wall-rock or associated with fragments or sheets of rock enclosed in 
the veinstone. Again, coarsely crystalline and even flinty quartz are seen to contain 
sparsely disseminated pyrite. Samples of these mineralized patches usually show on 
assay a gold-content varying from a few grains to 4 dwt. or 5 dwt. per ton, and a 
somewhat higher silvei-content. 



139 

Vugs in the veinstone, consisting of calcite and quartz pseudoinoiphous after 
calcite, are eouinion, and occasionally attain large dimensions. 

(3.) Oxidized vein-material is confined to the Waihi Mine, where the veins out- 
cropped or their apices approached the surface. In this mine, too, owing to struc- 
tural conditions admitting of the seeping of surface-waters to considerable depths 
through the wall-rock, oxidized veinstone exists below a zone of sulphide ore. In the 
Waihi Grand Junction and Waihi Extended mines there is practically no oxidized vein- 
stone. 

Ihe oxidized material represents the oxidized equivalent both of the non-payable 
vein-filling and of the sulphide ore. It is nearly everywhere more or less rusty, and 
is frequently stained throughout by black oxides of manganese, and contains a little 
clayey material. A few small patches here and there show greenish or bluish coatings 
of carbonate of copper. 

Near the outcrop of the -Martha lode all the different types of quartz described are 
to be seen. The more brittle and friable varieties aie usually ricliir tlian the liarder 
and tougher varieties. A good deal of the banded wavy quartz with rust-stained 
partings is no doubt the oxidized equivalent of banded sulphide ore, and evidently 
much of the rusty finely crystalline material represents oxidized non-banded sulphide 
ore. The carbonates liave been completely leached out of the oxidized veinstone of 
the upper horizons, and the downward percolating waters have effected a wholesale 
replacement of the carbonates by (juartz with the attendant lilieration of the man- 
ganese as the black dioxide. In the replacement which was effected by ascending 
siliceous solutions, it may be mentiont?d, the manganese was evidently removed with 
the lime. The oxides of manganese have in many places segregated, and occur as 
black cindery-looking seams, generally aligned with the plane of the vein, or, again, fill 
fissures in the neighbouring wall-rock. A sample from one of these seams contained — 
Manganese-dioxide (MnOj), 4Uiy per cent.; manganous oxide (MnO), 632 per cent. 

Oxides of nickel and cobalt are not infrequently associated with the manganese- 
oxides, and together constitute in places over 1 per cent, of the mass. 

Free gold was rarely visible to the unaided eye, even in the richest oxidized ore, 
but a " tail " of very finely divided gold (electrum) could be obtained by dish 
washing. The gold-fineness of the Waihi Company's plate bullion is 0'645. As 
argentite not infrequently occurs in the normal " oxidized " ore, the ratio of gold to 
silver in this ore is about 1 : 3 or 1:4. 

An analysis of rich oxidized ore from tiie Martha lode is given by Morgan* : — 

Per Cent. 
Moisture lost at 100° C. ... ... ... ... ... 0^(3 

Loss on ignition ... ... ... ... . . r60 

Silica .. ... ... ... ... ... 89-98 

Ferric oxide ... ... ... ... ... . . 562 

Alumina ... ... ... ... ... ... 182 

Manganese and nickel oxides ... ... . ... 0.39 



99-67 
Assay — Gold, 2 oz. .5dwt. 17 gr. per ton; silver, 10 oz. 2 ilwt. 12 gr. per ton. 

* '' Notes on the Geologv, Quartz Reefs, and Minerals of the Waihi Goldfield," by P. G. Morgan, Trans. 
Aust. IiiBt. Min. Eng., vol 8, 1902, pt. 2. 



140 

"An approximate analysis of oi-e (dry-cruslied mill sample) from surface to about 

400 ft." is given by Banks* : — 

Per Cent. 
Moisture ... ... ... ... ... ... 0'15 



Loss on ignition 

Silica 

Iron (oxide) 

Iron (sulphide) 

Manganese 

Lime ... 

Alumina 

Magnesia 

Undetermined .. 



0-73 

95-97 

0-93 

Trace. 
0-24 
0-25 
1-62 

Trace. 
Oil 



10000 

On the surface of the Martha Hill, and forming layers under the clays and soils, 
appear fragments of light-coloured very finely crystalline or cryptocrystalline quartz. 
Much of this material shows a banded structure, and is tinted various shades of 
brown, yellow, green, and pink. It differs little, if at all, from man}- of the siliceous 
sinters found elsewhere in the area. These may be surface-formed sinters referable to 
the " spill " of the vein-forming solutions, but this is doubtful, as patches of similar 
material occur in the veinstone at considerable depths below the surface. 

The Ore-shoots. 

Within the Waihi veins the ore occurs in fairly well-defined shoots, but in many 
cases the transition from ore to unprofitable veinstone is rather a gradual one. 
Itroughout many long stretches of the wide lodes only a portion of the total width 
is profitable, the remainder being formed of barren or low-grade veinstone, consisting 
mainly of quartz and manganiferous calcite, or its replaced and oxidized equivalents. 
Again, pay-ore occurs from wall to* wall over widths ranging up to 80 ft. or 90 ft. 
The gold and silver is, as already stated, almost invariably associated with sulphide- 
bearing veinstone, or its oxidized equivalent. 

The impregnating metal-bearing solutions are considered by the writers to have been 
genetically connected with the dacite boss which has been intruded into the bedded 
dacites. Furthermore, the intrusive dacite — the "productive" dacite — appears to 
have afforded a more favourable repositorj- for ore than the surrounding bedded or 
" inferior " dacites. Minor variations in the wall-rock, such as the degree to which 
propylitization has been effected, do not appear, however, to have greatly influenced the 
position and value of the ore. The Royal and other lodes in places often carried equally 
good ore where dark relatively little propylitized rock formed the walls, as where the 
moi-e altered " kindly country " occurred. Certain of the unconformity horizons in 
the bedded dacitic complex have associated with them zones of soft oxidized rock. In 
places this oxidized rock forms the foot-wall country of the Martha-Edward lode at 
No. 9 (1,000 ft.) level, Waihi Mine, and the band of sulphide ore which elsewhere 
occurred in the vicinity of the foot-wall is here non-existent. Sulphides have, how- 
ever, been developed at this horizon on the hanging-wall side of this wide lode where 
the unoxidized intrusive dacite constitutes the wall-rock. 

It is a striking feature throughout the field that the better-defined bands of 
sulphide ore generally occur in contact with, or little removed from, the vein-walls; 

* " Milling and Treatment at the Waihi Mine, N.Z.," by E. G. Banks, Trans. Aust. Inst. Min. Eng., 
vol. 8, 1911. 



141 

and, with the notable exception just cited, where unusual structural conditions exist, 
they are more frequently associated with tlio foot-walls. Furthermore, within the 
vein-filling itself the presence of sheets and isolated fragments of wall-rock appears 
to have favoured the precipitation of the sulphides and, pari passu, the gold and silver. 

Within the limits of the shoots the existence of wide circulation-channels, either 
in the form of open fissures or sheared zones, appears to liave favoured the deposition 
of ore fiom the ascending impregnating solutions. Thus the Edward lode, at No. 8 
(850 ft.) level, Waihi Mine, is richest where it measures from 75 ft. to 90 ft. wide. At 
this locality it is joined by the almost transversely striking Empire lode, and the latter, 
A\liich is here contracted in width, carries no pay-ore, although some distance away 
it is strong and productive. Similarly a local pinching of a vein is usually attended 
with the occurrence of low-grade veinstone, and such contracted parts are, for this 
reason, occasionally left as pillars between the ends of stoping-blocks. The junction 
of two veins which gradually converge upon each other either in strike or in dip 
naturally gives rise to increased widths, and stich junctions have frequently proved the 
loci of wide productive stoping-blocks. 

There are at Waihi no intersecting veins exactly comparable with the " indicators " 
or " flinties " of the Thames Goldfield, wiiich in places form almost a network in the 
wall-rock. In the No. 5 level of the Grand Junction, however, small pyritic and 
quartzo.se veinlets intersecting the wall-rock of the Empire and Royal lodes are said 
to be associated with the local enriclmients. 

Post-mineral fractures effecting displacements of the veins, factors which have 
had such a marked influence on the localization of ores in the bonanza fields of Thames 
and Coromandel, arc practically non-existent in the Waihi Mine and throughout the 
major extent of the Waihi Grand Junction Mine. The fault in the eastern workings 
of the Grand Junction appears to be but little younger than the formation of the 
vein fissures. Ore occurs in both the Royal and Enipire veins at the intersection of 
this fault, and subsequent movements have been attended with some reconcentration 
or enrichment of the gold-silver-bearing sulphides. 

In connection with the formation of veins at Waihi, considerations of the form 
and disposition of the vein fissures, of the fact that the original ajiices of many veins 
are .still existent, also of the character of the ore exposed from the surface to a depth 
of 1,000 ft., lead to the conclusion that the ore is mainly a product of primary 
deposition from heated ascending aqueous solutions. It has already been indicated 
that there are evidences of a rejuvenation of ore-bearing solutions having effected the 
deposition of sulphiile ore within tlie main mass of earlier-formed ore. These later 
banded sulphides, however, differ but little in chemical or physical character from 
those of earlier formation, and the parent solutions probably had a common origin. 

In the case of the Martha lode below where it outcropped on Martha Hill (Waihi 
Mine), oxidized vein-material occurred throughout the whole of the superficial horizons, 
and persisted, particidarly on the hanging-wall side of the vein, to depths of 700 ft 
or 800 ft. Similar conditions also obtained in the Welcome, Regina, and several other 
hanging-wall branches of the parent lode. Tlie sulphide ore fir.st made its appearance 
as narrow bands on the foot-wall side of the lodes. These bands gradually increased 
in dimensions as followed downward, and, in addition, isolated remnants of sulphides 
occurred and became progressively more and more conspicuous in depth. With regard 
to these sulphides, Morgan* remarks, " The first sulphide ore found in tlie Waihi 
Mine at the second level on the foot-wall of the Martha lode was of high grade, averag- 
ing 1 oz. to 2 oz. of gold and 30 oz. to 60 oz. of silver to the ton. The richest portions 
assayed up to 25 oz. gold and 1,000 oz. silver per ton." 

• P. G. Morgan, " The Hauraki Goldfields," N.Z. Mines Record, voL 8, p. 465. 



142 

These sulphides were evidently in part enrichments due to reprecipitation of 
secondary sulphides, and associated gold and silver, from solutions migrating down- 
ward thi-ough piiiiiary sulpliidcs from the zone of weathering. That similar sulphide 
enrichment extended to depths even below the limits of oxidation is also probable. A 
comparison, however, of the ore-values at, say, No. 8 level (850 ft. on the Martha 
lode) with ore-values on the Edward and Royal, which carried at their upper horizons 
little or no oxidized vein-material, suggests tliat the Martha at this horizon derived 
but little enrichment from downward-seeping solutions. 

Scarcely enough data are available for comparing the value of the oxidized ore of 
the Martha with that of the sulphide ore, but on tlie whole it would appear that the 
latter was the richer. A relative enrichment of the oxidized ore was effected by the 
removal of the calcite, pyrite, &c., and this may have almost counterbalanced any 
transfer of dissolved gold and silver to the underlying sulphides. 

In the Grand Junction Claim the fact that the original apices of the veins are 
intact and unoxidizcd has precluded any marked rearrangement of the gold-silver 
content as indicated above. The presence of ruby silver (proustite and pyrargyrite) 
and secondary pyrite in cleavages and cavities in some of the ore, particularly in 
the regions of faulted and crush zones, is, however, indicative of local enrichments. 
It may be remarked that the formation of secondary sulphides (pyrite) does not neces- 
sarily imply enrichment, as the pyrite found in the Mary and other lodes encrusting 
ore is notably poor. An assay of a sample of this pyrite yielded only 7 gr. of gold 
and 3 dwt. 11 gr. of silver per ton. 

The question as to the persistence of the Waihi ores in depth appears to be closely 
connected with the fundamental laws governing the solution and precipitation of 
metals under varying conditions of temperature and pressure. A comparison of the 
veins at the two horizons— No. 8 (850 ft.) level and No. 9 (1,000 ft.) level— in the 
Waihi Mine (that is, below the crests and flanks of the old Martha Hill) and at 
corresponding horizons — No. 4 and No. 5 levels — in the Waihi Grand Junction (that 
is, below the floor of the old depressed and buried valley lying eastward of Martha 
Hill) is suggestive. At No. 9 level, Waihi Mine, both the Empire and Royal lodes* 
show materially less ore than at No. 8 level. In the Grand Junction, at No. 5 level, 
however, both these lodes show increased ore-tonnages, and, on the whole, increased 
tenor as compared with the corresponding portions at No. 4 level. The relationship 
of ores to topography is usually attributable to secondary enrichment effected by 
chemical processes fsolution and reprecipitation of the metals) accompanying the 
erosion of the land-surface. At Waihi, however, the fact that the apices of both the 
lodes mentioned are either intact or almost intact precludes this explanation being 
advanced to account for such conditions. Apart from modifications due to the vary- 
ing volume, kinetic energy, and chemical composition of the impregnating solutions 
and the presence of mobile precipitants — gaseous or liquid — it seems probable that a 
more or less " critical level " of ore-deposition was determined bv the temperature 
and pressure conditions existing during the periods of primary ore-formation. Such 
a " critical level " would be expected to conform, in a modified degree, with the con- 
tours of the older dacites, and this in great part appears to account for the conditions 
obtaining at Waihi. (See page 65.) 

In the Union-Silverton section of the Waihi Mine the veins, as far as can be 
ascertained, occurred in the bedded dacities, and outcropped at the surface. The rich 
ores of the shallower horizons exhibited undoubted evidences of superficial secondary 



* The Martha lode has been materially affected by structural changes in the enclosing rock-mass, and 
comparisons have here been limited to the Empire and Royal lodes, which througrhout traverse the intrusive 
daoite. 



143 

enrichment. " Mustard " gold, not unlike that found in the weathered portions of 
telluride-bearing ores, was conspicuous, also rich veinlets and pockets of argentite. 
This electrum was evidently derived from the oxidation of sulphides. The identifica- 
tion of tellurium in some specimens of highly mineralized veinstone has, however, been 
recorded, although it has never been detected in the ores of the Martha Hill section. 
Tlie deei)er-level exploration in the Union-Silverton section revealed a giadual 
impoverishment of the ore in all the veins. 

The Waihi. Mine. 

The Waihi .Mine comprises several claims, having an aggregate area of 765 acres 
and 1 perch, and is tlie property of tlie Wailii Gold-mining Company (Limited), 
London. 

The history of the mine is briefly described in connection with that of the Waihi 

field generally. (See pages 9-12.) 

The total gold-silver production cannot be accurately stated, but the following 
tabulation may be regarded as a faiily close approximation : — 



Years. 


Ownere. 


Tons crushed 
(2,000 lb.). 


Yield. 


1879 


McCombie and Lee . . 


2 


£ 
3 


1883-89 . . 


Martha Extended Gold-mining Company 


28,496* 


17,370 


1885-87 


Rosemont Gold-mining Company 


123 


923 


1886-99 . . 


Silverton and Waihi-Silverton 


33,126 


48,346 


1887 


Union Gold-mining Company . . 


350 


2,735 


1899-1902 . . 


Union- Waihi (iold-mining Company 


36,865 


51,559 


1893-96 . . 


Cassel's Company (tailings only) 


29,772 


19,285 


1887-91 


Waihi Gold-mining Company, London . . 


Not knowii 


50,081 


1892-1910 . . 


Waihi Gold-mining Company, London . . 
Total 


3,685,970 


9,056,237 




£9,246,539t 



* Approximate. 

t The Waihi Mine must also be credited with most of the tailings dredged from the sludge-channel — 
the Ohinemuri Hiver — and re-treated. The Ohinemuri River Syndicate and the VV'aihi-Paeroa Gold-extrac- 
tion Company (Limited) have raised (1904-10) 51,135 tons of tailings, which on treatment yielded bullion 
valued at £1 4,0 14. 

Tlie Waihi Gold-mining Company is capitalized at £r)00,000, and the total 
distribution to shareholders to the end of the year 1910 was £4,251,554 68. 7d., or 
46'6 per cent, of the value of the output. 

Equipment. — The plant and equipment of the mine is necessarily extensive, and 
only the briefest description is here given. 

Six vertical rectangular shafts, as the plans will show, give access to the under- 
ground workings. Four of the shafts (Nos. 1,* 2, 3,* and 6) are sunk close to the 
Martha lode, which has afforded nearly one-half of the mine's output. Nos. 4 and 5 
are located in the hanging-wall country of the .Martha, and even at the 1,000 ft. level 
are distant from it about 625 ft. and 950 ft. respectively. 

Pumping plants in former years stood on Nos. 1 and 2 shafts, but at the present 
time the main pumping-station of the mine is No. 5 shaft. The pumping plant consists 
of two compound Cornish surface condensing-engines, known respectively as the " B " 
and the "C" pumps. They work at a steam-pressure of 1501b. per square inch, and 
the sizes are as follows: "B" pump — High-pressure cylinder, 35 in. diameter by 



* The No. 1 shaft is now used exchisivelv a.s an ore-pass, while No. 3, in the western section of 
the property, has been abandoned and the machinery removed. 



144 

6 ft. Gin. stroke; low-pressure cylinder, 70 in. diameter by 8 ft. stroke; plunger 
pumps, 16^ in. diameter by 10 ft. stroke; bucket pump, 17 in. diameter by 10 ft. stroke; 
duty, to raise 700 gallons per minute against a head of 1,000ft. "C" pump— High- 
pressure cylinder, 60 in. diameter by 6 ft. stroke; low-pressure cylinder, 110 in. 
diameter by 12 ft. stroke; plunger pump, 23 in. diameter by 12 ft. stroke; bucket 
pump, 24 in. diameter by 12 ft. stroke; duty, to raise 1,500 gallons per minute against 
a head of I,r)50 ft. 

As an increa.sed volume of water will be encountered below the 1,000 ft. level, and 
as the " B " pump has reached the maximum lift for whicli it was designed, electrically 
iliiven pumps of the 3-throw ram type are being erected at Xo. 4 shaft to replace the 
" B " pump in raising water from the 1,000 ft. level to the surface. The " B " pump 
will then be employed for further sinking, and will deliver at the 1,000 ft. level. The 
electrically driven pumps have rams of 12 in. diameter by 2 ft. 6 in. stroke, and 
have a maximum speed of forty-two revolutions per minute, at which speed they deliver 
1,500 gallons per minute. Producer-gas engines have been adopted as the prime 
movers for these pumps. 

Each of the shafts Xos. 2 and 4 is equipped witli a pair of cages, and Xo. o shaft 
with a single cage; all these cages are operated by steam-driven winding-engines. 
Ore is raised to the surface through the two first-named shafts, one truck liolding 
about 27 cwt. being raised each trip. Xo. 2 shaft is now being re-equipped, and will 
be fitted with twin cages, each holding two trucks placed side by side. Tlie main o)e- 
hoisting shaft (Xo. 6) i.s e(|uipped with two 3-ton self-dumping skips operated by a 
steam winding-engine. 

The surface equipment formerly on the Union-Silverton section of the mine has 
been dismantled and removed. 

The company owns three separate mills, each connected with the mine by rail — the 
Victoria, 200 stamps; the Waihi, 90 stamps; and the Union, 40 stamps. The Victoria 
mill is situated at Waikino, on the banks of the Ohinemuri River, and is about five 
miles and a half from the mine. The Waihi and Union mills are distant respectively 
about 40 and 60 cliains from the mine. 

The Victoria mill consists of rock-breakers (Gates and Heclon type), 200 stamps 
(weiglit 900 1b. to 1,2501b. each), running 102 to 105 drops per minute, eleven tube 
mills 18 ft. long by 4 ft. 9 in. inside shell diameter (ten running and one stand-by). 
The daily output is 970 tons. 

The Waihi mill consists of rock-breakers, ninety stamps, five tube mills (four 
running and one stand-by). Tlie daily output is 420 tons. 

The Union mill* consists of rock-breakers, forty stamps, and one tube mill. The 
daily output averaged 110 tons. 

Crushing and grinding at each mill is followed by amalgamation on muntz-metal 
plates and concentration on vanners of the Union and Wilfley types. 

The concentrate-treatment plant at Waikino deals with tlie product of all three 
mills, and consists of two tube mills, thickening-boxes, twenty-three conical-bottom 
air-agitation cyanide-tanks (16 ft. high by 6 ft. in diameter, worked in series), filter- 
presses, &c. 

A cyanide plant for the treatment of the sand and slime separately exists at each 
of the three mills. 

A brief description of the methods in vogue appears in another section of this 
report. (See pages 21-22.) 

* This hasjrecently been closed. 



145 



The bullion slime fioai the three mills is treated at one melt-house, situated at the 
Waihi mill. At the same mill is tlie Dore refining plant. For several years the 
sulphuric-acid process of lefining was in use. but this was discarded over two Vears ago 
in favour of the electiolytic method. 

The company possesses a well-equipped foundry at the Victoria mill, also worksliops 
and sawmills at both tlie Victoria and Waihi mills. 

Power to operate the mills is supplied by water, steam, and producer-gas. A total 
of about 2,800 brake horse-power is consumed by the three mills and treatment plants. 
The steam and gas power used at the mine in 1910 for pumping, winding, and air- 
compression is difl^icult to estimate owing to the winding-engines being used onlv 
intermittently, but it may be stated as equal to about 1,200 brake liorse-power. 

A liydro-electric power plant to deliver 6,000 brake horse-power is now under con- 
struction. The generating-station is on the Waikato lliver, at Horahora, fortv-ei-dit 
miles distant from the mine. When completed the mills will be operated entirelv bv 
water and electric power. At the mine it is proposed lo ajjply the power to the supple- 
mentary pumping plant, the air-compressors, workshops, subsidiary surface machinery, 
and to one ni- more of the winding plants.* 

Tht Martha Scr/ioii. — Derclopment : The Martha section of tlio mine has been 
developed from ten levels in addition to two or three adits. These levels open at the 
following deptlis : — 

137 ft. j 



No. 


1 


No. 


2 


No. 


3 


No. 


4 


No. 


5 


No. 


6 


No. 


7 


No. 


8 


No. 


9 



No. 10 



206 ft. 

279 ft. ) 

342 ft. \ 

432 ft. 

544 ft. 

704 ft. 

8.-)4 ft. 
1, ()')•{ ft. 
l,l.-)l ft. 



tlMow the collar of No. 1 shaft. 



t Below the collar of No. .") siiaft. 



The area coveiing the underground workings measures about 120 acres. The 
aggregate length of cros.scuts and drifts is said to approximate twenty-five miles, and 
of this a total length of over fifteen miles is still open. 

Several passes or subsidiaiy shafts exi.st, and through these material e.xcavated 
in opencuts on the crest and flanks of Martha Hill is transferred to the under- 
ground workings for filling the depleted stopes. 

Geological Struct iirr : The geological structure of the rock-masses enclosing or over- 
lying the veins has already been indicated in tiie text and in the plans and sections. 
It need only be remarked that the undeiground workings liave disclo.sed botli the 
intrusive and the bedded vein-bearing dacites, the more recent andesites, and the 
rhyolites. 

The Veins nntf Ore-deposifx : The disposition of the principal veins and their 
relationship to .structural features have already been described. As previou.sly men- 
tioned, the Martha lode outcropped on the crest of Martha Hill, but disappeared on 



* For'further'information regarding tho Waihi Company's mining and milling plants, and details of 
working, see " Pumpinfj Machinery for Mines " (with special reference to the plant at the Waihi Mine. N.Z. ). 
by W. Percival Gauvain ; "Mining Methods in the Waihi Mine, N.Z ," by Ja.s. L. Gilmour Jind 
W. H. John.ston ; " Milling and Treatment at the Waihi Mine, N.Z.," by E. O. Banks ; " A Review of Modern 
Gas-power Practice," by S. E. Fra.ser : all in Trans. Aust. Inst. Min. Eng., vol. 8 (1911). 

t The collars of No. 1 and No. 5 shafts are respectively 419"Gft. and 410 ft. above sea-level. 

10 — Waihi-Tainia. 



146 

the eastern Hanks of the liill beneath the mantle of younger barren rocks. Tlie down- 
waid extension of the workings revealed the fact tliat the Martiia was but the parent 
lode of a great vein-system. The official reports of the company show that up to the 
year 1910 no less tlian twenty-one veins, counting together the stronger ore-bodies 
and their various branches, have contributed to the mine's output. The principal 
veins and their biaiiciies may be giouped as follows: — 

Maltha lode — 

Hanging-wall branches — Welcome lode 

Regina lode. 
Magazine lode. 
Victoria lode. 
Surprise lode. 
Foot-wall blanches — Xo. 2 reef. 

.Martha north leader. 
Empire lode — 

Hanging-wall branches — Albert lode. 

Alexandra lode. 
Foot -wall branches — " H " lode. 
" I " lode. 
" J ■• lode. 
" K " lode. 
" L" lode. 
Princess lode. 
liM\ al lode- - 

Hanging-wall branch — North Royal lr)de. 
Foot-wall Ijranch — Rex. 

Edward lode. 
The tabulation submitted showing the tonnage of ore raised in each separate year 
from 1898 to 1910 (inclusive) and the sources from whence it was derived affords a 
criterion of the past importance of the various veins. 



TONXAGES* CONTRIBUTED BY THE VARIOUS LoRES TO THE MiXE's OuTPUT DURING PERIOD 1898-1910 

(inclusive). 

















i 










Year. 


eS 


£ 


T3' 


£ 


. 




^£ 


'i 


= 


.2 


i 




5 


8 


1 
■a 


■p. 
S 


c' 


d 


55 


1 


1 


1 


•s 




S 


^ 


H 


H 


as 


^ 


Z 


rt 


S 


> 


33 


1898 


37,462 


30,200 
















10,267 




1899 


49,.598 


36,498 




9.30 








1,956 


1,386 


12,013 




1900 


44,070 


48,140 




9,622 


397 






3,034 


2,999 


3,210 




1901 


5.5,465 


59,865 




29,424 


242 






6,627 


5,598 


1,687 




1902 


81,372 


31,102 




47,185 


262 


67 




7,877 


4,872 


103 




1903 


102,296 


32,499 




.50,216 


1,346 


1,089 




8,893 


5,963 


5,309 


1,637 


1904 


98,339 


41,746 




.50,161 


12,125 


2,553 




13,684 


6,753 


5,735 


743 


1905 


134.463 


35,296 




43,874 


24,613 


339 




23.578 


2,507 


582 


97 


1906 


146,409 


41,721 


8,069 


33,846 


.39,671 


132 


61 


17,212 


10,078 


1,855 




1907 


177,800 


43,5.39 


13.239 


45,660 


46,645 


1,346 




4,339 


2,252 


3,871 




1908 


206,431 


43,017 


37,069 


42,198 


43,302 


9,603 




318 




1,065 




1909 


203,726 


45,290 


36,108 


42,420 


70.216 


2,089 




14,944 








1910 


226,442 


46,.501 


45,601 


63,165 


51,860 


16 




5,841 




423 




Totals (in 


1,620,105 


569,020 


140,086 


481,206 


291,404 


17,679 


61 


113,352 


45,716 


50,719 


2,763 


short tons) 

























•Previous to 1905 the tonniiKPs .tip in lone tons : hence addition of the vertical columns does not give the stated totals. — En. 



147 

Tonnages* contributed by the Various Lodes to the Mines Output during Period 1898-1910 

( INCLUSIVE ) — continued. 



Year. 



^ (]> o 

o •SE-' 
>.ofeo 

a PX! 



1898 
1899 
1900 
1901 
1902 
1903 
1904 
1905 
1906 
1907 
1908 
1909 
1910 



149 





417 




0.4 10 




11,652 




19,933 




19,321 




12,231 




7.530 


1,289 


731 


360 





53 



2,324 


3,699 


4,173 


4,837 


1,819 


3,682 


3.4 IG 


3,849 


115 


4,152 


1,528 


1,208 


2,665 





51 



205 
2,014 
4,204 
2,527 
2,310 



391 




417 




5.551 




6.731 




3,457 




3,062 


852 


3,076 


240 


855 


161 



613 



1,198 



87,280 
114,667 
125,453 
178,444 
201,023 
259,082 
291,176 
298,531 
328,866 
356,974 
393,214 
416,813 
442,020 



17,038 22,893 57 12,031 41 , 26,309 1,253 3,493,543 



Totals (in .'short 1,649 79,489 6 

tons) .1 

* See note on preceding page. 

T/te Martha Lode. — The Marlha lode, wliich has been responsible for about lialf the 
total output t'loni the mine, has been exploited within the Waihi Mine over a total 
length of 2,900 ft. On its easterly trend it passes into tlie Waihi (Jrainl Junction, 
but on its westerly trend it splits into parallel strin^eis, and apj)areiitly lias, even at 
the upper levels, little or no persistence beyond the western boundary of tlie Waihi 
property. 

In tiie adit levels its width varied from ."> ft. to 50 ft. In Xos. 1, 2, and ."i levels 
the most easteily drift*; and slopes revealed the vein-cap protected from erosion by 
the overlying barren rocks, t'cutlu'riiij.' out to a mere .seam. This is apiiaicntly tiie 
original apex of the lode. 

The tal)ulation on pages l.").'i-.")4. compiled from the plans and otlicial reports, 
embodies the available information respecting the lengths and widths of tlie vein and 
of the ore-shoot disclosed at the several levels. 

The main ore-slioot on the Martha thus shows an average stope-length of 1,300 ft. 
It is, on the whole, disposed witii a pitcli at hii^h angles (say, 75°) to tlie eastward, 
and from 300 ft. to 400 ft. of barren or low-grade veinstone separates it from the 
shoot wori<ed in the Waihi Grand Junction Mine. 

Tlie fact tliat the .Martha outcropped strongly, and that much of the veinstone, 
especially on the hanging-wall side, was very permeable, led to surface-waters effect- 
ing oxidation to depths of over 700 ft. Sulphide ore, however, made its appearance 
at No. 1 (137 ft.) level, although throughout only a short stretch of the lode, the 
remainder of the ore being completely oxidized. From here downward at each sub- 
sequent level the (piantity of sulphide ore increased gradually, but was confined mainly 
to the foot-wall part of the lode. 

At \o. 5 (432 ft.) level what was classed as sulphide ore amounted to over one- 
third of the veinstone, and extended on the foot-wall side over practically the full 
length of the shoot. 

No. 7 (70ift.) level, as the figures will show, proved the best yet opened on the 
Martha, and affoi ded a large tonnage of sulphide ore and a considerable amount of 
oxidized ore. The bulk of the sulphides, as at shallower horizons, occurred in the 
north or foot-wall portion of the lode. 



10 *— Waihi-Tairua. 



148 



--''i--m2Leve/(l05) 



No. 8 (S.'jil't.) level proved to be below the limits of extensive oxidation, and the 
liiiiniiitic staiiiings and tlie segregated iiiaii<ranese-oxides were confined to streaks, 
vug.s, and fractures. Although more extensive stretches of unpayable veinstone 
occurred at this level than at No. 7, sulphides were found thrcjugliout fairly long 
stretches, l)eing generally distrilnited from wall to wall of tlie lode. Tlie sulphides 
were still, however, more prominent towards the foot-wall. Tlie nature of the vein- 
stone at No. 8 level may be gauged fiom the fact that blocks stoped on the shrinkage 
system measured in places over 50 ft. wide, the roof standing without support. 

No. 9 level reveals markedly different conditions from those obtaining above. 
Although tlie strength of the lode is here well maintained (average width, 57"3 ft.), 
and one or two stretches show paj'-ore over the full width, much the greater length 
of the lode carries sulphide ore only as a band 10 ft. to 14 ft. wide. This band is 
confined to the hanging-wall side. From this ore-streak to tlie foot-wall, excepting 
in the ea.stern end of the mine, exists cavernous oxidized veinstone. This is mainly 

a quartzose replacement after calcite. 
Surf sec rust-stained with iron-oxides or black- 

ened with manganese - oxides, and 
carries very low or negligible amounts 
of gold-silver. This occurrence of 
oxidized veinstone below a horizon 
showing little or no oxidation is coin- 
cident with the existence of a belt of 
brown oxidized propylite, which forms 
the foot-wall country, for variable 
thicknesses up to about 90 ft. from 
the lode, but does not appear on the 
*/ hanging-wall. The belt of jointed 

oxidized rock, which resembles surface 
country, has dipped and gradually 
encroached on the lode from the north- 
west, as have also several carbonaceous 
seams found in the foot-wall country 
between No. 6 and No. 9 levels. These 
seams represent the vegetation of old 
land-surfaces — periods of quiescence in 
the intermittent volcanic activity which 
yielded the bedded dacites. It is pos- 
sible that the deep-seated oxidation is 
in part that due directly to ancient 
surface conditions, and has resisted 
the effect of subsequent hydrothermal 
action (propylitization). It is more 
probable, however, that some of these 
ancient surfaces or unconformities, per- 
haps partly reopened by earth-move- 
ments, have afforded channels whereby 
oxidizing waters have seeped from the 
surface. A continuous " weeping " of 
some of the carbonaceous seams, even 
in the relatively dry portions of the 
woikings, has been observed. 




Sea Level 



// ■■■l'/.'I 
,Ll-M-.M-8 Level (880') 



f/{! 



md Level. (lOOO) 



BOSS-SECTION ON Maetha Lode (Waihi Mine). 

(rt.) Ore and unprofitable veinstone (oxidized). 

(6.) Sulphide ore (main mass). 

(c.) Unprofitable veinstone (oxidized). 

Note. — Horizontal scale = twice vertical scale. Boundary 
of ore in block between levels Nos. 8 and 9 inferred. 



140 



The change of the locus of the sulphide ore from the foot-wall to the hanging-wiill 
of the Martha is evidently not due to the existence of the oxidized belt described, 
since in the eastern end of the No. 9 level workings, where no oxidation of the wall- 
rock exists, the same change in position is disclosed. The Martha between Nos. 8 
and 9 levels, as previously mentioned, in the main follows the contact of the intru- 
sive (" productive ") and the bedded (" inferior ") dacites, the former here constitutin"- 



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150 

the lianging-wiill cdiiiitiy, tlic lattor tlie foot-wall country of tlie lode. At shallower 
horizons the " piodnctivc " 'lacite constituted both walls. Change in stiuctural con- 
ditions has therefore probably iiad its influence on ore-deposition. From the appear- 
ance of the oxidized veinstone at No. 1) level it seems unlikely that its poverty in 
gold and silver is due to any leaching which accompanied o.xidation. Much of the 
j)seudomorphous change from calcite to quartz at this liorizon appears to have been 
effected by waters migrating down the unconformities mentioned. Prior to the 
replacement and o.xidation this portion of the lode underlying the hanging-wall sul- 
phide band \^ as evidently a mass of white manganiferous calcite, in jilaces replaced 
or partly replaced by quartz, enclosing ribs and sheets of fissure-filled ijuartz, and 
containing veiy spaisely distributed small sporadic bunches of sulphides. Many such 
sections as tiie one under mention are to be seen on tliis lode, and at approximately the 
same level (No. 5) in the Waihi Grand Junction Mine. 

BrancJu'S of M<irth(i : Certain Iji'anches of the Martha, as tabulated, constituted 
important ore-1)odies at the shallow and mid levels, but these, having proved eitlier 
non-existent or of no importance at No. 9 (1,003 ft. level), call for little description. 

The AVelcome was the most important of these lodes, and from its junction with 
the Martha on strike at the shallower levels was followed westward for over 2,000 ft. 
Still further westward some 500 ft. it has been worked just beyond the Waihi 
boundary in the Grand Junction western claim, thus proving a stronger vein in this 
direction than what is regarded as the Martha proper. The Welcome, which on the 
whole varies fiom .j ft. to 50 ft. w'ide, stands nearly vertical, and makes a south- 
westerly pitching junction with the Martha. Its main ore-shoot had a maximum 
length of about 1,350 ft. at No. 2 level, and, pitching eastward, necessarily became 
shorter and shorter in depth. Up to the end of 1910 it had afforded a larger 
tonnage of ore than either the Empire, Edward, or Royal lode. The ore, in character 
and extent of oxidation, differed in no respect from that of the Martha. 

At Nos. 8 and 9 levels from the bend on the Martha-Welcome-Edward only unim- 
portant ribs f)f (juartz have been proved by crosscutting to persist westward on the 
normal easterly lines of the Martha and Welcome fissures. The official reports refer to 
the Welcome section of the main crescent-shaped lode at No. 8 (854 ft.) level. This 
stretch is about 175 ft. in length, and has afforded a considerable tonnage of pro- 
fitable ore, as the taljle on page 155 will indicate. 

The corresponding " Welcome section " at No. 9 (1,003 ft.) level consists almost 
entirely of oxidized low-grade or barren veinstone similar to that forming the foot-wall 
part of the Martha. The same oxidized belt of rock continuing round from the foot- 
wall of the Martha here forms the foot-wall of this " Welcome section." 

Of the Regina, Magazine, and Victoria, foi-mer important contributors to the 
mine's output, only the first-named is still identifiable at No. 9 (1,003 ft.) level. The 
Kegina, as far as developed, carries liere no pay-ore, except in one or two small flat- 
lying hanging-wall branches, which exhibit streaks of argentite. 

The " No. 2 reef," a foot-wall branch of the Martha, in the upper and mid levels 
intersected the " productive " dacites, and yielded over 17,000 tons of ore. When 
followed down the vein entered the bedded or " inferior " dacites, and here a marked 
impoverishment of ore and finally a contraction of the vein fissure was disclosed. At 
the lower levels this vein is of no importance. 

The Empire lode. — The Empire lode has a maximum extension within the Waihi 
Mine of about 1,600 ft., persisting eastward from the EdAvard lode to and beyond the 
boundary into the Waihi Grand Junc£ion Claim. From No. 7 (704 ft.) level upward 
the buried or exposed flanks of the Martha Hill limit the Empire's easterly extension. 



151 

and at Xo. 1 (].57ft.) k-vel it^ lenj^tli does not exceed 27.J ft. At this No. 1 level the 
lode averaged not more than 2 ft. in widtli, and at a sjiort distance above this it 
evidently feathers out in the enclosing dacites. From Xo. 6 (541 ft.) level upwards 
fissuring of tlie wall-rocks has been pronounced, antl the Empire thi'ows off several spur 
veins — the Albert, " H," "I," "J," " K," and " L " veins. All of these have yielded 
ore, but have in depth terminated or become unprofitable. 

The tabulation on page 155 shows, better than any detailed de.scription, the develop- 
ment of the Empire from a mere stringer neai' the surface to a strong ore-body at the 
lower levels. 

Little examination of tlie veinstone at the uppei' levels was possible, as the lode 
was stoped out at the time of examination. As might l)c expected from the truncation 
of the vein on the eastern flank of the hill, some oxidation of the ore was reported 
at the shallower horizons. Sulphides existed, however, even at Xo. 1 (137 ft.) level, 
and it would appear that there lias been vo-y little reairangement of the gold-silver 
content by descending waters. The average value of the ore from Xo. 5 (-132 ft.) level 
to Xo. 8 (854 ft.) level .shows remarkable uniformity. At Xo. 8 (854 ft.) level) the 
Einpiie has associated witli it a hanging-wall branch or loop vein — the Alexandra, 
which afforded a consideraljle tcumage of ore — but at Xo. !) (1,003 ft.) level this branch 
has shown pronounced impoverishment. 

It would appeal' that the Iviipiie ore-shoot may at lower hoiizons be continuous 
from tlie Waiiii Mine into the Waihi Grand Junction. Although a blank stretch exists 
in the vicinity of the boundary at Xo. 8 (854 ft.) level, ore appears in the present 
face of the drift at Xo. 9 (1,003 ft.) level, within 150 ft. of the boundary, and has 
in the Grand Junction Mine, at the corresponding level, been followed to this 
boundary. In any case, short blanks, or low-grade stretches within the shoot, aie, on 
other parts of Xo. l) (1,003 ft.) level, not unconunon. Tlie oie-slmot, on the wliole, 
appears to have a pitch at high angles to the eastward. 

Throughout its whole course, at all levels, the Enipire lode lies within the intrusive 
or " productive " dacite. 

The Uoynl Lode. — The Hoyal lode is one of the most persistent ore-bodies on the 
field, and has been provetl to carry ore, with occasional short runs of low-grade vein- 
sttme, over a length of 3,600 ft. Of this stretch, over 2,250 ft. lies within the Waihi 
Mine. 

The development of the Royal lode when followed from the old surface downward 
is similar to that of the Enipire. At Xo. 3 (279 ft.) level, above which it extends 
about 80 ft., it extended from flank to Hank of the old hill (365 ft.), and liad an 
average width of 5'5 ft. The average value of the ore here (iJ2 Is. 7d. per ton) 
differed l)ut little from that at No. 7 (704 ft.) level, although oxidizing waters must 
have had some access -to the vein-channel. The tabulation on page 156 gives a snmmaiy 
of the available particulars regarding the extent and strength of the vein and the 
dimensions and value of the pay-ore at the several levels. 

It will be seen that, as in the case of the Empire, the Xo. 8 (854 ft.) level has 
proved the best yet opened on the Royal lode, and that the Xo. 9 (1,003 ft.) level, 
as far as developed, shows a marked impoverishment, notwithstanding an increased 
width of veinstone. 

The Royal lode, as already stated, appears to lie just within the southern limits 
of the intrusive or " productive " dacite, and on its western extension, beyond the 
junction of the Edward lode, probably enters the bedded or " inferior " dacites. 

Neither the hanging-wall branch of the Royal, the North Koyal, nor the foot-wall 
branch, the Hex, has afforded profitable ore, although small sporadic bunches and 



i5'2 

patches cairyiiig siiljiliides occur in Ijotli of liicni. In Xn. 5 and succeeding levels the 
I>oith lioyal was follow etl some distance in ciosscutting from No. 5 shaft for the 
Royal and Empire lodes; while at No. 7 (704 ft.) level the Ilex was prospected by 
drifting for a stretch of 1,00U ft., and at No. 8 (8o4 ft.) level for 400 ft. The small 
tonnage of ore milled from the JJe.x was obtained during the course of this prospecting- 
work. In the ujiper levels the veinstone of both tlie reefs consists mainly of platy 
pseudt)morj)hous (juartz, with ribs of normal crystalline quartz and some calcite. As 
lower levels are reached the calcite becomes more prominent. The North Royal shows 
at No. 9 level a contraction of the vein fissure with, at frequent intervals, unfilled 
spaces or cavities. The Rex reef, althougli in itself of little or no importance, has 
had the effect of materially strengthening the main Royal lode eastward of its 
junction. In fact, from the Rex junction the Royal strikes north-east on the con- 
tinuation of the Rex line rather than on its normal almost easterly course. 

The EJuard Lode. — The Edward lode is in many respects the most remarkable 
in the Waihi Mine, and promises to prove at the lower levels the most important ore- 
producer. On the wliole, this lode strikes about north-south, and stands nearly 
vertical. The shallowest level from which it lias been worked is No. 5 (432 ft.), and 
above this it was followed about 70 ft., where it was found to split into small veinlets, 
and feather out in the enclosing dacites. At No. 5 (432 ft.) level its average width 
was only 4 ft., and its longitudinal extension 473 ft. Tlie tabulation on page 1.37, 
compiled from otlicial data, shows its development, level by level, down to No. 9 
(1,003 ft.). At levels No. 6 (544 ft.) and No. 7 (704 ft.) it extended as a cross-lode 
from the Welcome to the Royal. At levels No. 8 (854 ft.) and No. 9 (1,003 ft.), 
however, the Edward is continuous, from the western extremity of the Royal, with the 
Welcome and Martha, trending as a single boomerang-shaped fissure. 

The marked increase in width of the Edward below No. 7 (704 ft.) level will be 
noticed from the tabulation; so, too, will the hif/her tenor of the ore at No. 8 
(854 ft.) level compared with that both above and below. With the exception of the 
extraordinary concentration of rich ore in the wide lens at No. 8 (854 ft.) level, the 
ore of this lode from the apex to No. 9 (1,003 ft.) level exhibits a fairly uniform 
average value. Tlie extent of oxidation of the Edv ard ore at and above No. 8 level 
is practically negligible. The rich banded sulphides which have raised the tenor at 
the level named are evidently not derived from the leaching of sulphides of upper 
horizons, but originated from a deep-seated source. The wide, rich lens, it may be 
pointed out, occurs at the point where the Empire junctions with the Edward, but 
the latter lode is in this vicinity small and of little value. 

The Edward at No. 9 level has opened up more satisfactorily than any of the 
other lodes. The ore-tonnage here exceeds that which existed at No. 8 level, and its 
average value, although less than at the latter horizon, is more than equal to the 
average at the other three levels. 

Developmental work was not far advanced on this lode at the time the writers' 
examination was made. It was, however, observed that the oxidation which had 
affected the Martha and Welcome had partly affected the neighbouring northern 
portion of the Edward, and was even observable in the western portion of the Empire 
and Alexandra lodes where they approached the Edward. The western wall-rock of 
the Edward, where exposed, was the bedded dacites, and there seems little doubt but 
that the lode is here following approximately the contact between the intrusive or 
"productive" and the bedded or "inferior" dacites. It is possible, therefore, that 
below No. 9 (1,003 ft.) level further oxidized wall-rock may exist. The channels of 
undero-round water-circulation, however, are so diverse that there is no certainty as 
to the extent to which such oxidation may have occurred. 



153 



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158 

The rnion-Silverton Section of the U'riihi Mine. — The Union-Silverton section of 
the Waihi Company's property is situated within the iiilier or " island " of old dacitic 
rocks forming the group of hills rising above the plain about 40 chains south-east of 
jMartha ilill. These liills — the Union, Amaranth, Silverton, and Kosemont — rise loO ft. 
to 250 ft. above the low-lying country which skirts them. 

The principal workings are included within an area of about 50 acres. Three 
main reefs — the Union, the Silverton, and tlie Amaranth — liave been worked. 
The value of the gold-silver production from this section is not ascertainable, as the 
ore mined by the Waihi Company prior to the formation of the subsidiary Union- 
Waihi Company was bulked with that derived from the Martha section. In the 
tabulation submitted 70,464 tons of ore, valued at £103,563, is definitely referable to 
the Union-Silverton area. 

The three reefs mentioned, as well as several minor veins, were at the outset 
worked from opencuts and from adits hx small prospecting companies. At a later 
stage of development shafts were sunk, and at least six of these can be counted. The 
Union No. 1, situated between the Union and the Amaranth reefs, and the Silverton 
No. 1, sunk near the Silverton reef, gave access to the principal workings. 

No mining has been done on the Union-Silverton section since the year 1901, and 
all the pumping and winding machinery has been dismantled. Although the pumping 
in the Martha section partly unwaters these old workings no examination by the writers 
was pessible, and the descriptions given are mainly drawn from existing plans and 
mining reports 

From the Union No. 1 shaft (collar-elevation, 404 ft.) levels are opened at the 
following intervals: No. 1, 131ft.; No. 2, 200ft.; No. 3, 280ft.; No. 4, 365ft.; 
Xo. 5, 450 ft. ; No. 7, 650 ft. And from the Silverton No. 1 shaft (collar-elevation, 
432ft.) at the following intervals: No. 1, 98ft.; No. 2, 172ft.; No. 3, 252ft.; 
No. 4, 333 ft. ; and No. 6, 533 ft. 

The country rock, as far as can be judged from an examination of the partly 
oxidized dump material, consists of altered pyroxene andesites and dacites referable 
to the bedded or inferior group of the older series of Waihi volcanics. As in the 
typical inti'usive dacite of the Martha section, secondary orthoclase (valencianite) 
partly or wholly replaces the plagioclastic feldspar (andesine). 

There can be little doubt but that the veins of the Union-Silverton section were 
formed synchronously with those of the Martha Hill section, and are, indeed, but the 
southern members of the system. Subsequent mining development may prove that the 
Union lode is directly connected with the Rex or one of the other branches of the 
Royal lode. Numerous " blows " of siliceous sinter are prominent on the Silverton 
Hill area. Some of these have been undercut by adits, and are found to have no per- 
sistence in depth ; others seem to be more directly connected with the auriferous 
veins of the area, and are probably the deposits from the "spill" of the vein-forming 
solutions. Hydrothennal action has resulted in pronounced alteration of the whole 
rock-mass. The country is veined in all directions by quartz, and is in places so 
highly silicified that its original character is completely masked. 

As the plans will show, both the Union and Amaranth lodes are practically con- 
formable in strike and dip with the Empire and Royal lodes of the Martha section. 
The Silverton lode, however, lying further eastward, strikes north— south, or ti-ansversely 
to the general direction, and dips to the westwaid at high angles. 

The veinstone of the Union, Amaranth, and Silverton lodes differs little, as far 
as the gangue is concerned, from that found at the shallower horizons in the Martha 
section of the claim. The ore of the dumps exhibits evidence of widespread quartzose 
replacement of calcite, with accompanying deposition of finely crystalline quartz in 



159 

open fissures. The veinstone is, as usual, stained with iron and manganese oxides. A 

few remnants of sulpliides, pyrite, and a little clialcopyrite were observed. Selenium 

was detected in the year 1889 " in the black ore from the old Rosemont Mine,"* and 

the presence of both the telluride and the sulpho-antimonide of silver, as well as 

galena and chakopyrite, is suggested by an analysis of a samj)le of rich ore from the 

same claimf : — 

Per Cent. 
Silica ... ... ... ... ... ... 89-.3 

Alumina ... ... ... ... ... ... 15 

Proto.\ide of iron .. ... ... ... ... 5'94 

Lime . . ... .. ... ... .. 049 

Sulphide of lead ... ... ... ... ... 005 

Suli»lii(U' of copper ... ... ... ... ... 0"06 

Sul})hide of antimony . ... ... ... ... 0-.'302 

Gold .. . ... , ... ... 0-021 

Silver ... ... ... . ... ... 1149 

Tellurium . . ... ... ... ... Trace. 



98-812 

A sample of ore from the Union lode submitted for analysis was descril)cd as 
follows: "Amorphous and crystalline (piartz containing clectrum in pale-yellow 
grains, and also a telluride of silver, proI)aI)ly hessite, in the form of dark-grey 
streaks of granular mineral; assay, 66 oz. gold and 186 oz. of silver to the ton. "J 

Finely granular argentite was, from all accounts, abundant in lenses of rich ore 
mined even fiom the siiallow adits. This led to the shipment to smelters of .selected 
parcels of high-grade ore prior to the introduction of the cyanide process. The 
o.xidized equivalent of this lich sulphide ore was frequently described as peppered 
throughout with very finely divided gold. 

The occurrence of calcite in any appreciable (|uantity, even at the lowest levels 
opened of these veins, has not been reported — that is to say, the quartzose replace- 
ment at these horizons has apparently been complete. Drawing an analogy from 
conditions obtaining in the Martha .section, the primary carbonate may be expected 
to occur here at greater depths. 

Th-e Union Lode. — This vein, which has afforded more than half the ore raised 
from this section, has a proven longitudinal extension of 1,300 ft., drifting to this 
extent having been done in No. 2 level from the Union^ No. 1 shaft. In Xos. ■{, 4, 
and 5 levels the lode was followed for 875 ft., but at No. 7 level the crosscut fi-om 
the shaft was distant 150 ft. from the vein wlien operations in the mine were discon- 
tinued. 

The Union, according to the Mines report of 1888, showed a gradual increase in 
width from No. 1 down to No. 3 (280 ft.) level, where it averaged from about 5 ft. 
to 6ft. At the Xo. 4 level (365ft.) its strength was equally well maintained; but at 
the No. 5 level, 85 ft. deeper and the lowest drift opened, the width scarcely averaged 
2 ft. The vein, moreover, is here considerably disjointed, and in places only a few 
stringers represent its track. 

The length of stopes showed a maximum at No. 2 (200 ft.) level, here measuring 
1.000 ft At No. 4 level the stope-lenjrth was much l<'ss,|| and the ore milled 



• By Mr. Alex. Montgomery, then Director, School of Mines, Thames. Mines Rep., 1889, C.-2, p. 20. 

t Analysis by Jas. Pond, Colonial Analyst, Mines Rep., 1887, p. .^G. 

I Analysis by Wm. Skey. Mines Rep., 1887, p. 24. 

II Exact figures not obtainable. — Ed. 



160 

yielded, on the average, £1 lis. per ton. At No. 5 level no stoping was done, as the 
reef showed little or no ore. 

In connection with the crosscut opened from the shaft at No. 7 (650 ft.) level, 
and driven 200 ft. towards the reef, mention should be made of the intersection of 
several small veins of quartz. The largest of these was met about 35 ft. from the 
shaft, and assayed 13 dwt. of gold per ton. On the whole, the character of the country 
and of the small veins in this crosscut is reported to be favourable. 

The Amaranth Lode. — The proven extent of this lode in the drift at No. 1 level 
or adit is 1,300 ft., and its width varies from 10 ft. to 25 ft. The pay-ore disclosed 
here was confined to a stretch of 160 ft. on the hanging-wall side. The width stoped 
ranged from 3 ft. to 7 ft., and the value averaged about £2 per ton. To exploit this 
shoot at greater deptli, a crosscut was extended from the Union No. 1 shaft at No. 3 
(280 ft.) level. The lode was intersected vertically under the line of the shoot, but 
here measured only 5 ft. wide, and was unprofitable. A drift was advanced 150 ft. 
without disclosing pay-ore. The above-mentioned work, it may be stated, covers the 
whole of the prospecting and development yet done on this lode. 

The Silverton Lode. — The Silverton lode has been proven on its strike for a dis- 
tance of 825 ft. It ranged in width from 5 ft. to 15 ft., with an average of about 
10 ft. The pay-shoot near the surface was not more than 40 ft. long, and enclosed 
small pipes or lenses of rich oxidized ore with remnants of sulphides high in 
argentite. At No. 2 (172 ft.) level the stope-length on pay-ore was 490 ft., 260 ft. 
of this being north and 230 ft. south of the shaft. At the No. 4 (333 ft.) level the 
pay-streak shortened to about 230 ft., the vein-width being about 7 ft. The average 
value recovered from 27,525 tons of ore milled between March, 1897, and March, 
1899, was £1 lis. 5d. per ton. At a depth of 533 ft. (200 ft. below. No. 4 level) a 
crosscut has been advanced 185 ft. from the shaft. This should have intersected the 
reef had it preserved its normal westerly dip. A 4 in. vein alone was cut at the 
160 ft. mark, but as the main lode shows in places a warped structure, eSecting change 
of the main Silverton dip, it may possibly in the low-level crosscut be still ahead of the 
face. 

The Mascotte Lode, running nearly parallel to both the Union and the Amaranth, 
and about midway between them, is traceable for about 600 ft. In tlie surface adit it 
was represented by two closely associated parallel veins. At No. 1 level from the 
Union workings the lode was cut and driven on for 240 ft. It here varied in width 
from 15 in. to 24 in., and produced some profitable ore. At the Union No. 2 level, 
69 ft. deeper, the Mascotte was again intersected (being here 3 ft. to 5 ft. wide), and 
followed 150 ft., but disclosed no profitable ore. From an old shaft — the Silverton 
No. 3 — the lode was cut at a corresponding horizon to the last named and 500 ft. 
further eastward, but with no better results. 

Statistics, Exploratory Work proceeding and propoxed, dec. — Ore-reserve : Re- 
garding the ore-ieserve of the Waihi Mine, the following statement appears in the 
company's annual report for the year ending 31st December, 1910 : " The total 
amount of pay-ore in sight developed by drives both over it and under it is 
1,068,334 tons. Besides this there is a quantity of payable ore amounting to 

600,697 tons locked up in arches and pillars supporting the various levels and shafts, 
some of which can only be won gradually, and at additional expense, from time to 
time as levels become obsolete." The estimated value of the ore in reserve is not stated. 
The fieures quoted have been augmented by subsequent developmental work at No. 9 
(1.003 ft.) level. 



161 

Oictput: Tlie output of tlic mine in IDlO anmuntcd to ■i42,0'JO tons, valued at 
.£926,100, but ou the i-esults of recent developmental work a reduction has been found 
necessary, and the amount now being mined is equal to about 320,000 tons per annum.* 

Exploration: The principal developmental work now in progress is the further 
opening of the Martha section of the mine at No. 9 (1,003 ft.) level, and the driving 
of the main crosscut at No. 10 (1,151ft.) level to intersect the various veins. 'Ihe 
country being penetrated at the latter horizon, it may be stated, is similar to that 
encountered at corresponding positions in the levels above. 

Heretofore the increased amount of ore which each succe.ssive level down to No. 8 
(8.")-t ft.) revealed, together with the heavy expenditure which drainage at the lower 
horizons entailed, has determined the policy pursued in respect to the rate of down- 
ward development. In view of the sudden decrease in the amount of ore which the 
opening of No. 9 level has disclosed, the ore-reserve cannot be considered large, and 
consequently an acceleration in the rate of shaft-sinking and opening levels below 
Xo. 10 is contemplated. 

The only diamond-drilling e.\ploration done by the company has been on the 
horizontal. The advisability of initially e.\ploring in depth the veins or vein-bearing 
country and enclosing rocks by tiiis method has always been deprecated. Tlie main 
argument cited against drilling is the friable and cavernous nature of much of the 
vein.stone. Notwithstanding this disadvantage, the writers are of the opinion that 
boring in the past would have proved of value, and the advisability of projecting 
several well-directed boreiioles from workings to be opened at No. 10 level is worthy 
of favourable consideration. 

With regard to lateral exploration, it might appear from a casual examination 
of mine-plans that developmental work has been unduly restricted to an area of some 
120 acres out of a total claim-holding of over 76.") acres. Regard, however, must be 
paid to the positions of the old buried contours which limit the Martha Hill area of 
vein-bearing dacite. As seems likely from the records, the boreholes projected from 
the end of the south-east crosscut at No. 8 (854 ft.) level reached the unconformity 
" slide " between the dacites and the barren andesites, so that exploration — beyond 
that actually done — at this or siiallowor horizons was not warranted. At No. 9 
(1,00-3 ft.) level an exploratory cro.sscut is l)eing projected from the drift on tlie Royal 
lode towards the Union-Silverton workings. In addition to penetrating a long stretch 
of unknown country, this tunnel will drain the Union-Silverton secticm of the mine, 
and will afford a minimum of 550ft. of "backs" below the lowest drifts already 
opened on the veins. Beyond the limits of both the .Martha and I'nion-Silverton 
sections, and within tiie portion of the Wailii Company's claim which stretches out 
on the plain, it is by no means unlikely that the barren volcanics overlying the older 
dacites may persist in places to or even below the horizon of No. 10 level. 

Remarks on the future prospects of the mine are inchuled in the sunmiary chapter 
dealintr with the Waihi field generally. 

Wnihi Grnml Jvnrtion Mine. 

The Waihi Grand Junction claims comprise two separate areas of country, aggre- 
gating 791 acres 2 roods 3 perches, and are the property of the Waihi Grand .Junction 
Gold Company (Limited), London. 

The eastern and bv far tlie more important area, which measures 190 acres, 
adjoins the Martha section of the Waihi Mine, and contains extensions of the Martha, 
Empire, and Royal lodes. 



* The output for 1911 wa.s 31fi,349 tons, valued at £670,179. 
ll_Waihi-Tairua. 



Fons milled 


Value of Yield. 


m = 2,0001b.). 


£ s. d. 


9,0.38 


12,591 1 


40,220 


68,2.37 18 6 


48,477 


72,941 3 


59,147 


100,687 17 


84,226 


133,31.5 2 



162 

The westcin aioa lies to the westwiud and northward of the Waihi Company's 
property, and measures 601 acres 2 roods 3 perches. The only vein proved to exist 
here is an extension of tlie Welcome lode of tlie Waihi Mine. 

The hi.story of the mining deveh)pment of tlie Grand Junction has been outlined 
in connection with that of the Waihi field generally. 

Tlie gold-silver production has been practically all derived from the eastern 
section, and is as follows : — 

Year. ,, . 

(1 ton 

1906 
1907 
1908 
1909 
1910 

241,108 £387,772 19 8 

The Waihi Grand Junction Gold Company ('Limited) is capitalized at £400,000 
(400,000 shares of £1 each, of Avhich 385,000 shares have been issued). The total 
distribution to shareholdeis is referable to the operations of the year 1910, and 
amounted to £19,218 15s. 

Equipment. — One main vertical shaft gives access to the underground workings 
of the principal portion of the property, and, in addition, a small old shaft serves the 
purpose of an air-way. The main shaft is provided with two haulage compartments 
for single cages, a ladder-way and pump compartment, the spare portion of the pump 
compartment being also divided into two hanlage-ways. For haulage an electric 
winding-engine and a supplementary steam winding-engine are employed. 

Pumping is only carried on during sliaft-sinking and initial crosscutting, since 
the main unwatering of the whole of this portion of the field is effected by the pumps 
of the Waihi Company. Electrically driven pumps are employed in shaft-sinking. 

On the western section of the company's property two shafts, the " B " and the 
" C," have been sunk, and an old winding plant exists on the former. No work 
has, however, been done here since the year 1908. 

The company's mill is about 20 chains Histant from the main shaft of the eastern 
section, and is connected therewith by a Bleichert aerial tram. It is a well-arranged 
modern mill, consisting of Hadfield crushers, forty stamps (1,1001b. each), eight tube 
mills, sizing and classifying machinery (spitzkasten, Wilfley tables, kc), cyanide 
plant, and all the usual accessories. 

Power is generated at a centi-al station bv means of Parsons steam turbines, and 
is transmitted electrically to the mine and mill. Steam-driven air-compressors here 
supply power for the underground drills and compressed air for the milling plant.* 

Grand Jvnction, Eastern Section. — Under r/rminfl Development: This section has 
been developed from five levels opening from the main shaft, at the following intervals 
below the collar: No. 1, 315ft.; No. 2, 493ft.; No. 3, 636ft.; No. 4, 793ft.; 
No. 5, 944 ft. The collar of this shaft has an elevation of 376 ft. above sea-level, 
and is 33^ ft. below the collar of the Waihi Company's No. 5 shaft. The Junction 
Company's No. 4 and No. 5 levels are therefore 27'5 ft. and 25'5 ft. above the Waihi 
Company's No. 8 and No. 9 levels respectively. 



* For further particulars resjardins the millingr 'plant 'and methods emploved, see " Metallurcrjcal Process 
of the Waihi Grand .Junction Gold Compinv (Limited), Waihi, N.Z.," by Alexander Fvfe. Trans. .4ust.. Inst. 
Min; Eng., vol. 8, 1911. 



163 

As the cross-sectional plans will sliow, Xo. I level penetrated only the younger 
barren andesites overlying tlie vein-bearing daeites. No. 2 (493 ft.) level merely 
pierced the apices of the Martlia lode and its two foot-wall branches — the No. 2 and 
the Mary. No. 3 level commanded blocks on the same three lodes, but exploration 
southward revealed only younger andesites. Nos. 4 and •') levels have opened up the 
lodes named, and in addition the Empire and the Hoyal. At No. 5 level both the 
Empire and Royal have much greater extension eastward than No. 4 level, and various 
branch lodes — the George, Grace, &c. — as well as minor independent veins, have been 
discovered. 

Geoloc/icdl Stnirtiiff : The geological structure as exhibited within this portion of 
the Waihi Grand Junction Mine has been desci-ibed in connection witli that of the field 
generally. 

The depth to which the overlying barren rock — the rliyolites and younger ande- 
sites — persisted, j)articularly in tlie soutli-eastern portion of tlie ground, has rendered 
initial mining development both tedious and expensive. Of far greater importance, 
however, is the recognition of the fact that (he vein-bearing rocks are divisible into 
the " productive " dacite and the " inferior " dacitc, depending mainly upon whether 
the rock-masses are intrusive or bedded. 

The ea.stern limits of the intrusive dacite are, at No. .") (944 ft.) level, approxi- 
mately marked by a line of faulting sweeping round from near the foot-wall of the 
Royal lode not far from the Waihi - Waihi Grand Junction boundary, and probably 
meeting the hanging-wall of tlie Martha hxle about 200 ft. west of the Waihi Grand 
Junction - Wailii Extended Ixuindary. To the eastwaid of this line of faulting the 
Royal lode and its loop vein, tlie George, are represented only by erratically disposed 
sheets of barren or low-grade veinstone. The Empire, offset to the southward about 
16 ft., carries a slioot of sulphide ore for 137 ft., and then feathers to a stringer. The 
Grace lode, a hanging-wall bianch of the Martlia, is offset to the south some 20ft., and 
from heie shows impriverishment. The Martlia lode in the (Jrand Junction has not 
i/cen explored eastward to the fault-line. It, however, seems uidikely that the fault 
will persist thnnitrli tlie Martha, I)ut will rather be foun<l to follow the hanging-wall 
side of this large lode. Tlie shattered, slickensided, and broken country encountered 
in the Waihi Extended Claim southward from the hanging-wall of the Martha is 
probably an expression of this same ground-movement. 

The change of country .southward and eastward of the fault-line is evidenced by 
the occurrence of coaly partings in the main soutii-east cro.sscut projected beyond the 
Royal lode, and in the crosscut driven northward from the Empire lode at 975 ft. 
east of the main cros.scut. Again coarse-textured propylite (the " inferior " dacite), 
almost like an altered diorite, was penetrated in the short crosscut projected south- 
ward from the Martha at 1,040 ft. east. Eastward of the fault-line, moreover, 
erratically disposed slieets of tpiartz and numerous slickensides are common. 

On the north side of the Martha lode evidences of unconformity — change of 
country — are no less evident. In the crosscut at No. 4 (793 ft.) level from the 
Martha lode to the Mary, and located 200 ft. eastward of the Waihi - Waihi Grand 
Junction boundary, coaly partings are visible in the rock about 25 ft. from the foot- 
wall of the Martha. At No. 5 (944 ft.) level the Mary lode is enclosed altogether in 
the " inferior " daeites. Still nearer the Martha at this level, carbonaceous bands 
dipping to the south-eastward at about 45° are conspicuous in the drift on No. 2 lode 
from 250 ft. to 350 ft. eastward of the main crosscut, and the coarse diorite-like 
propylite is prominent at 400 ft. eastward. No crosscut connection from the No. 2 
lode to the Martha eastward of the main crosscut had been made at the time of 
11 •— Waihi-Tairua. 



164 

exainiiiiition, and as to how far from No. 2 lode towards the Martha these " inferior " 
dacites extend is unknown. The ea.sterly diift on tlie Martha itself exposes verv little 
of the country rock. Enough has been stated to show that the " inferior " dacites 
form alnio.st an encircling l)elt in the Grand Junction, extending from a point just 
northward of the Martha lode at the Waihi Company's boundary eastward about 
1,400 ft., and tlience round south of tlie Royal and George lodes to the Waihi 
Company's boundary again. From the main mass of the intrusive or " pi-oductive " 
dacites a nariow offshoot extends towards the Waihi Extended Company's workings, 
along the line of the Martha and Xo. 2 lodes 

The occurrence of faults within the area of intrusive dacite is, in the Grand 
Junction Mine, as in the adjoining Martha section of the Wailii Mine, practically 
unknown. 

Tlie Veinx: The lodes on the horizon of the No. 5 level have been indicated on the 
plan. Sufficient data for the tabulation of the ore-values of the several lodes at the 
different levels are not available, but the following description of each lode — the Martha, 
No. 2, Mary, Grace, Empire, Royal, and George — may be submitted : — ■ 

The Martha Lode: The Martha lode eastward from the Waihi Company's boundary 
has been exploited at all levels from No. 2 (49-3 ft.) to No. ij (944 ft.), and has within 
this vertical range developed from a comparatively small to a very strong vein. As 
an ore-producer it has, however, proved disappointing, having so far shown deteriora- 
tion rather than improvement as followed downward. At No. 2 level the total drift- 
length, measuring from the Waihi boundary, is 375 ft., and average width 8 ft. At 
No. 3 level tlie drift-length is 925 ft., and average width 23 ft. At No. 4 level the 
drift-length is 1,250 ft., and average width 35 ft. At Nc. 5 level the drift-length is 
1,460 ft., and average width 45 ft. In levels Nos. 2 and 3 the lode is terminated to 
the eastward by the old contour of the vein-bearing dacites, but at the two lower levels 
veinstone exists in the present faces. 

The ore within the shoots extended from, wall to wall of the vein where the width 
was not great, but elsewhere it was confined to the foot-wall part of the lode — a 
barren calcite, replaced or partly replaced by (|uartz, forming the remainder. The 
sulphide ore, which is of later formation than the calcite, is in places sharply separated 
by a slickensided selvage from the latter, or, again, invades it irregularly. 

The blocks stoped, as will l)e noted from the sectional plan, are, on the whole, of 
rather indefinite shape. The ore-tonnage showed an increase down to No. 4 level, but 
no improvement in value was recorded, the amount of low-grade veinstone intimately 
associated with the streaks of 'iclier ore rendering the bulk-value low. 

No. 5 (944 ft.) level revealed a marked diminution in the amount of ore compared 
with the level above. The only stoping-block here measures 125 ft. in length, and the 
streak of pay-ore (value about £1 8s. per ton) does not average more than 8 ft. to 
9 ft. wide. With the exception of this block, the great mass of veinstone opened in 
the drifts and subsidiary crossciits at this level consists of white manganiferous calcite, 
quartzose replacements after calcite, and ba-ids of fissure-filling quartz. This material 
shows an average value of from 2s. to 3s. per ton. Small sporadic bunches carrying 
sulphides are occasionally noticeable, particularly in the vicinity of tlie walls or 
included sheets of country. 

No. 2 Lode: No. 2 lode, a branch striking off the foot-wall of the Martha and 
running almost parallel with the parent lode, has been followed eastward at all levels 
to, or almost to, the Waihi Extended boundary. Over a stretch of 475 ft. it has 
afforded a fair tonnage of ore, which has, on the average, proved of higher grade than 
that mined from the Martha. Below No. 3 level, or an intermediate 70 ft. lower than 



165 

Xn. J, a marked decrease botli in Muaiitity and ([uality occurs, and No. ."> level has 
disclosed no millable ore. The contrast between the strength and value of the vein 
at No. 2 level and at No. 5 level is a marked one. At the former horizon some of 
the stopes measured over 20 ft. wide, and showed liigh-grade sulphide ore both of the 
curly banded and replacement types. At the No. 5 level the vein is represented by a 
weak contracted fissure, seldom over ."> ft. or G ft. wide, partly filled witli (juaitz and 
calcite, and is in many places merely a seam. Over a long stretch at this horizon the 
vein is enclosed in the " inferior " dacites, and will probably feather out at no great 
depth below. 

The M(ir;/ Lode The Mary lode branches from tiie foot-wall of tlie Martlia 
within the Waihi Mine, and has probably there been foUowed for 80 ft. on the No. 8 
level, but identification has not been established. In tlie (Jrand Junction it has been 
drifted on* nearly to the Waihi Extended boundary in Nos. .'5, 4, and ") levels. At 
No. 2 level a few associated parallel stringers represented its ajiex. In the three 
other drifts ore has been obtained over the greater p(ution of its course, and 
althougii tiie value is, on the whole, decidedly erratic, a relatively large tonnage of 
millable ore is being developed. The width of the Mary varies up to 1") ft. or 16 ft., 
but the walls over long stretches are very irregular and pooily defined. At No. 5 
(I)i4 ft.) level, which was^ihe first driven on this lode and the only one examined by 
the writers, the lode throughout its cour.se is enclosed in the coarse-textured " inferior " 
dacites. It is stated tliat tlie average value of the ore here is less than at No. 4 level, 
and it would seem that further impoverishment with depth is to be expected. 

The (iract Lodt : The Grace lode has been recently intersected in a crosscut pro- 
jected fiom the Martha drift to the Empire, at a point 820 ft. east of the main cro.ss- 
cut. At the point of intersection this vein, which is a hanging-wall brancii of the 
Martha, and separateil from the latter by only 16 ft. of country, measures over 20 ft. 
wide, and includes 7 ft. of a sulphide ore-band worth £2 7s. 6d. jier ton. l"\illowed 
eastward its strike carries it further and furtlier from tlie .Martha, and at the 160 ft. 
mark it is dislocated and thrown 20 ft. to the southward by tlie main fault. Beyond 
this fault tliifting is proceeding, and short stretches of millable ore iiave been recorded, 
with, however, a diminishing stiengtii of vein. 

Empire Lode: The Empire lode has been followed eastwaril from tiie Wailii Com- 
pany's boundary — at No. 4 (793 ft.) level, a distance of 675 ft., the drift-face here 
exposing barren veinstone; at No. 5 (944 ft.) level, a distance of 1,375 ft., the drift- 
face here being 137 ft. beyond the main fault, and showing only stringers of quartz. 

At No. 4 level the lode averages about 15 ft. wide, and consists mainly of calcite 
and quartz, with certain stretches on the foot-wall side showing a band of sidphide ore 
ranging up to about 4 ft. in width, and lensing (;ut in places to a mere selvage. The 
pay-ore mined here measured about 300 ft. on tlie stope-length (175 ft. to 475 ft. from 
Waihi boundary), and extended about 60 ft. above the level. In the back of the 
stopes the vein contracted to small dimensions. 

At No. 5 (944 ft.) level the lode averages 40 ft. wide for a stretch of 500 ft. 
(measuring from the Waihi boundary), and from here eastward the width is about 
15 ft. Both the unprofitable veinstone and the ore have practically the same cliarac- 
teristics as at No. 4 level. The ore-band here shows increased length and width as 
compared w ith the level above, and for the stretch of 450 ft. stoped (40 ft. to 490 ft. 
eastward of Waihi boundary) averages about 10 ft. wide. The reported value for a 
length of 308 ft. on No. 5 level was £2 12s. 6d. per ton. 

* Mostly since the writers' examination was made. 



166 

All uimsual section was exliibited liy the Empire where iiitei.sected by tlie main 
ciusscut, veinstone being here jjenetrated for (iTo ft. A width of 33 ft., measuring 
from the foot-wall side, sliowed, in addition to a band of sulphides, isolated Wocks 
and sheets of country enclosed in white siliceous and kaolinitic matei-ial (see page 137) 
spaisely impregnated with ]jyrite. This 33 ft., with the e.\ception of some bands of 
country rock, gave an average value of £^'2 12s. per ton. 

Eastw^ard of the ore-shoot described, and separated from it Ijy about 800 ft. of 
low-grade or bairen veinstone consisting mostly of calcite and cavernous white pseudo- 
morphous quartz, a minor shoot occurs at the intersection of the lode by the main 
fault. The lode east of the fault is displaced about 16 ft. to the southward, and here 
carries sulphide ore for 137 ft., the average assay being £4 9s. !)d. for a width of 
50 in. The extent of this shoot above the level has not yet been determined. Beyond 
the shoot drifting has shown, as previously mentioned, a feathering-out of the vein 
fissure. 

ZV/e Roijal Lode: The Royal lode has been followed eastward from the Waihi 
boundary in No. 4 (793 ft.) level 490 ft., and in No. 5 (944 ft.) level 1,200 ft. 

At No. 4 level the lode is over 20 ft. wide at the boundary, and this width is 
maintained for about 135 ft. eastward. Beyond this point it splits into branching 
loops, the fissuring evidenth' weakening on approaching the eastward-plunging apex 
of the vein, and finally terminates at about the 490 ft. mark. The sulphide ore-band 
which is coi. fined to the foot-wall side, and is overlain by white barren quartz-calcite, 
has been stoped, on the shrinkage system, for a length of 155 ft., and for a vertical 
height of from 80 ft. to 100 ft. above the level. Here the vein feathers out. On this 
level the value for a stretch of 131 ft. is given as £2 15s. per ton over an average width 
of 15 ft. 

Eastward of the block stoped streaks of sulpliide ore of good grade occur here and 
tliere for a distance of 215 ft., but these are in most cases too small and scattered to 
render a stoping-width of the veinstone profitable. 

At No. 5 level the Royal has been opened for 1,200 ft. — that is, from the boundary 
to the fault-line which crosses the strike of the lode 738 ft. eastward of the main 
crosscut. Throughout this stretch it is a well-defined vein having an average width 
of about 25 ft., thus showing materially increased strength compared with its exposure 
at the level above. Moreover, fiom its foot-wall it strikes an important branch or loop 
vein, the George. 

Two shoots of pay-ore are disclosed in the drift at No. 5 (944 ft.) level. These are 
separated by a stretch of 350 ft. of veinstone, which, although low grade over a 
stoping-width, carries, for the most part, streaks of sulphide ore of fair quality. 

The western shoot — the same as that worked at No. 4 level — here extends from the 
Waihi boundary to a point 240 ft. eastward. The drift itself for this distance exposed 
an average width of 65 in. of ore, valued at .£1 17s. 2d. per ton. Crosscuts through 
the vein at points distant 7 ft., 67 ft., and 157 ft. from the boundary were reported 
to show, respectively, widths of 21 ft., 15 ft., and 16 ft., and average values of 
£2 7s. 4d., £1 12s. 4d., and .£1 4s. 2d. per ton. A stoping-block about 200 ft. long 
is here being worked, its eastern end being determined by a vug of unusually great 
dimensions. 

The eastern shoot measuies about 658 ft., following the sinuous course of the 
lode, and the official figures respecting widths and values on the level may be quoted. 
The drift itself for a length of 26 ft. showed an ore-band 28 in. wide, assaying 
£3 6s. 5d. per ton, and for a further 738 ft. yielded an average assay value of £2 5s. 
per ton. Measuring from the main crosscut eastward a crosscut at 80 ft. gave 
£1 Is. 7d. for a width of 21 ft., a crosscut at 160 ft. gave 9s. for a width of 27i ft., 



167 

a crosscut at 27(J It. gave £2 Us. Dil. ioi a widtli oi io It., a crosscut at .'JoO ft. gave 
£1 14s. for a width of 13 ft., a crosscut at 420ft. gave £1 lUs. ;kl. for a width of 
23 ft., a crosscut at ."jIU ft. gave £-i Is. for a width of 36 ft., a crosscut at GOU ft. 
gave £3 Is. 8d. for a width of loft., a crosscut at 690 ft. gave £1 13s. 6d. for a 
width of 54 ft.* 

The No. 5 level on this ore-shoot is proved by rises to be, on the average, only 
about 50 ft. below the apex of the lode. Near the fault in the eastern end of the 
level, wiiere the lode shows a width of 54 ft., it persisted upwards only 20 ft. This 
abnormal width of veinstone so near tlie ape.\ is due to coniiilicated faulti)ig having 
brought about a duplication, or at least a bulging, of the lode.f 

Eastward of the fault-zone — the fault is here a composite one — tlic Uoyal might 
have been expected to be thrown to the southward, as were both the Empire and the 
Grace lodes. A crosscut to the southward showed no trace of it. An offset crosscut 
to the northward, however, revealed at 61 ft. a 24 in. baud of ijuaitz assaying 
7s. 5d., and at 7.*^ ft. a 9 ft. band of ipiartz assaying lis. 3(1. Hoth these bands strike 
about 25° more northward than does the Royal for some distance westward of the 
fault-line. It is i)rul)able that the 9 ft. vein represents the continuation of the Royal 
lode bending northward. On the other iiand, since the cap of the Royal west of the 
fault persists ujjwaid only 20 ft. above No. 5 level, and is plunging to the eastwai'd, 
theie is a possiI)ility that it !ias, eastward of the fault-line, l)een brougiit below the 
horizon of No. 5 level by ilownthrow. Exploration at No. 6 level will alone settle this 
tjuestion. 

7'/ie (Jeorijf l.ntli- : The (jcorge loile is a foot-wall brancli nf the K(i\al, .striking 
off the latter at No. 5 level at a point 160 ft. east of the main crosscut, and, like the 
parent lode, tlips to the northward at high angles. For a length of 260 ft. from its 
junction the Gcfirgo can ies ore valued at tl 19s. 6d. per ton over an average wultli 
of 55 in. Heyond this it is cut off by one of the faults associated with tlie main 
easterly bieak in tlie country. Alr)ng this fault, wliich also at 690 ft. east inter.sccts 
the Royal lode, some deposit inn of ([uaitz-calcite veinstone has taken place, l)ut this 
carries no ore. In an offset crosscut a small vein ranging from 1 ft. to 3 ft. (! in. 
wide ha.s been discovered about 40 ft. southward of the George, and on the south- 
eastern side of the fault. This vein, wiiich in places carries ore ranging up to £2 14s. 
per ton, is again involved furtlicr eastward in I)roken country associateil witli tlie 
fault-zone. 

The Geoige lode, like the Royal, persists above No. 5 level to a height of about 40 ft. 
or 50 ft. 

Other Veins: In addition to tiie veins mentioned, several minor ones have been 
found at No. 5 level. Near the Waihi boundary a vein about 10 ft. wide, carrying 
only low-grade veinstone, brandies north-easterly from the hanging-wall of the P>mpire. 
This may prove to be identical with the vein known as N<i. 3, which occurs in the 
vicinity of the main shaft, but which has as yet afforded no pay-(ue. 

The south-easterly crosscut projected from the easterly end of the Empire drift 
has disclosed two bands of (piartz, varying from 3 ft. to 4 ft. wide, and assaying only 
a few shillings per ton. The i<lentity of these veins has not been established. They 
are approximately on the line of strike of the Royal lode, but are over 500 ft. eastward 
of the fault-line. 



•Of this 54ft. crosscut, if 1.3ft. of valueless material near the centre of the lode be excluded, the value 
of thf remaining 41 ft. is £2 4.s. 2d. per ton. 

t The Cambria and other lofie.'; at Thames show a remarkable bulging or " blowing-out " on nearing 
the Moanataiari Fault. Bull. No. 10 (New Series), N.Z. G.S., p. 102. 



i lie W cslcni, Stclion, U (u/u Griiiul Juiicliun ttnu/i. — TLu wc'sLcin siuctiuii, wliicli 
^uvurs, ai> already staled, uvui' GUI aciLs, iueludcs claims ioiuicily worked by the \\ ailii 
Consuls and \\ ailii boulli guld-miiiiug eomijariies of Auckland. fcJuvcral old sliat'ts 
exist uu this aiea, and from two of them, the " li " shaft aud the " C " shaft, suuk 
by the W aihi Graud Junetiuu L'omi^auy, some e^pioratiou has been done. 

The " B " shaft is situated withiu jU ft. of the W aihi Company's western boundary, 
and appioxiniately on the strike of the Welcome lode. At intervals of 160 ft. and 
210 ft. lespectively below the collar (elevation, oifi ft.), levels have been opened on the 
Welcome, which here appears to be from (i ft. to £i ft. wide. A small tonnage of 
oxidized ore of fair quality was mined, but since iyU8 no work has been done. The 
vein at tlie 16U ft. level extended westward about 70 ft.; and at the 270 ft. level, 160 ft. 
westward from the Waihi Company's boundary. Ihe cap of the vein here plunged 
to the westward at an angle of about io°, beyond which only recent barren andesite 
existed. 

The "C" shaft (collar-elevation, ^o5 ft.) is situated 'J40 ft. from the boundary, 
and was sunk to a depth of 500 ft. xSo examination of these workings was possible, 
but evidently only the barren andesites were penetrated. From a level driven to a 
point below workings from " 13 ' shaft a rise-connection was made with the latter. 
The Welcome lode at the 500 ft. level is reported to have extended about 300 ft. from 
the Waihi boundary, at which point it terminated, but no reliable data are available 
regarding the conditions here. 

A borehole sunk by tlie Waihi South Company some 18 chains south-west of the 
Grand Junction Company's " C " shaft was reported to have been penetrating the 
barren andesites when abandoned at 1,500 ft., thus indicating the existence in this 
locality of a very deep old valley, or, indeed, the possibility of these andesites being 
at this point intrusive. 

Statistics, Exploration proceeding and proposed, d'c. — Ore-reserve: The ore 
blocked and ready for stoping in the Waihi Grand Junction Mine at the end of the 
year 1910 was, in the company's annual report, stated as 132,900 tons. Ore partly 
developed, exclusive of that revealed in winzes sunk from No. 5 (9i4 ft.) level, was 
estimated at 30,000 tons. The reserve ore is presumably about equal in grade to that 
milled during the year. 

Output: The total output of the mine for 1910 amounted to 84,226 tons, which 
yielded £1 lis. 8d. per ton; and for 1911 was approximately 94,603 tons, which yielded 
£150,729. 

Exploration : Lateral exploration on all levels dow n to and including No. 5 
(944 ft.) in the principal portion of this company's holding has practically reached 
the limits advisable. At present the main shaft is being sunk to provide for another 
level at 150 ft. below No. 5, and winzing is also in progress from No. 5 level. As it 
has been found uneconomical to develop the whole of this section from No. 1 shaft, a 
new shaft is being sunk about 1,000 ft. eastward of the former. This new connection 
with the surface will permit of the exploration of the relatively large area of ground 
still further to the eastward. 

The only boring-exploration done by the Grand Junction Company was confined 
to sinking one hole from the shaft-chamber at No. 2 (493 ft.) level. This borehole 
was projected at an angle of about 26° from the vertical to strike the Martha lode at 
1,000 ft. from the surface, and penetrated veinstone for a drilling-distance of 260 ft. 
Both the log and the available bore-samples are unsatisfactory, and no survey of the 
hole for deflection was made. Considerable doubt, for one reason or another, more- 
over, is cast upon the authenticity of the reported ore-values. Sulpliide ore of good 



Jb atu^ntnaiv/ Stxllfitm 2^*^ /.5. 



Wa:hi Grand Junction Gold C? 





Cross Section on Line K-K' 

(Striking N 17 W and passing through point 30ft east 
of Wdihi Grand Junction tJ- I Shaft) 

Showing geological structure, veins, and 
principal workings 



Wa.hi cm, CQ 



|- Waihi Grand Junction Cold C9 



^ 



Waihi 



C . M - C9 



^^_ 



SEA LEVEL 



G0Obelo>*Se9lerrl Bi^ded. CinfeA,>ld(u 










: JihyoZi.ti.c ::z formation. — — 

— — — - - — Position of conta(X^o-^l:i ^9^proAJjnate_jr^. ^^y 








jr^Le>d ffr^ir'} 



Froho^l'^y 



ieA<W* 



vnT'^'-' 



(Reptile crosscut from N? S le'el norlungs . Martha Hii/ secOi 
nil/ come under Union norkiiigs o fetr feet abore thii fioriion } 



€00 behi Sea lerel 



Cross Section on Line K^-K^ 

(Passing through Waihi Grand Junction Cos N° I Shaft and Waihi Cos Union N?l Shaft 

Showing geological structure and principal workings 

Scale of Feet 



l>ram.hyG.EJ!oms 



Sn Muthorit^ jon^ tlaoKaif Govemrrent Printer. 




169 

grade was reported to exist on what were presumably both the hanging- wall and tht 
foot-wall portions of the lode. Subse(iuent dcveh^pniental work at the No. 5 (944 ft.) 
level lias not disclosed the existence of a hanging-wall sulphide band. The lower end 
of the bore (where the foot-wall ore-band was cut) was some 2')0 ft. below No. 5, the 
deepest level yet opened. The advisability of sinking several boreholes from No. 6 
level, sliortly to be opened, will, after geological examination, be worthy of favourable 
consideration. 

Keinarks regarding future prospects are included in the summary chapter dealing 
with the Waihi Goldfield generally. 

W'uihi Extended Claim. 

The Waihi Extended Claim (area, lit) acres 2 loutls; owners, tlic \\ ailii Extended 
Gold-mining Company, Limited, Auckland) is a block of ground tlie main portion of 
which measures approximately 57 chains by 17A cliains, and adjoins on its soutiiern 
boundary the Waihi and the Waihi Grand Junction claims. Other contiguous claims 
are the Waihi Ueefs Consolidated and the Pride of Waihi. 

Since 1895 the Waiiii Extended has been owned and worked by the present pro- 
prietary company, and about £40,000 has been expended in its development. Both 
the Martha lode and the No. 2 lode have been found to extend into the claim from the 
Waihi Grand Junction, but so far no shoot of pay-ore has been discovered. 

Access to the workings is afforded by a vertical rcctangulai- shaft 12 ft by 
4 ft. in the clear. Ecjuipment consists of a winding-engine, which operates a cage 
and bailing-tank, also a hoisting-winch, used while sliaft-siuking, and an air-com- 
pressor. Steam-power is employed. A forty-stamp mill at Maratoto, formcily the 
property of the Waitekauri Extended Company, was purchased by tlic Waihi Extended 
Company some years ago, but so far the prospects of the claim have not warranted 
its being shifted. 

The shaft, which is sunk on the plain, has a collar-elevation of ;J!)8'5 ft., anil from 
it live levels have been driven at the following deptlis : No. 1, ."500 ft. ; No. 2, 500 ft.; 
No. 3, 654 ft.; No. 4, 805 ft.; and No. 5, 960 ft. 

Geological Structure. — Underlying the surface-gravels and clays rhyolitic rocks 
were penetrated in the shaft to a depth of 230 ft., and the younger andesites to about 
785 ft. — a depth at which the older dacites were reacheil. These older dacites, how- 
ever, were first encountered in the 500 ft. level about 370 ft. from the shaft, and in 
the vicinity of the Waihi Grand Junction boundary. They here enclosed the No. 2 }eef, 
but were found to persist eastward from this boundary only about 130 ft., where they 
gave place to the younger andesite. This old land, pitching towards both the cast- 
north-east (the direction of vein-strike) and the south-east, is evidently tlie tail of the 
buried spur extending from Martha Hill. Each successive level has afforded an 
increased area of the old dacites, and at the 960 ft. level a crosscut extending south- 
east from the shaft penetrated these rocks, and at 415 ft. intersected the Martha lode. 

The geological structure of the old dacites in the W'aihi Extended Claim is com- 
plicated. What is apparently the intrusive or " productive " dacite of the Waihi and 
Waihi Grand Junction claims is recognizable here as a comparatively narrow belt or 
sill, making irregular contacts with the coarse-textured " inferior " dacite. The best- 
defined contact between these two rocks appears at the 960 ft. level, about 100 ft. 
westward of the shaft, here striking north-south and dipping eastward at an angle 
of 35°. This contact-plane passes through the shaft at a point about 15 ft. below the 
960 ft. level, and from here for 80 ft. down (the deepest point reached at the time of 
examination) the " inferior " dacites — very coarse-textured propylites, almost like 
altered dioritic or granitoid rock — were penetrated. 



170 

It would ap]>ear fioiu an fxamination of the uiipei-level woikiiigs that the No. 2 
hxlc, wheie best 'lelineil and carrying small pockets of ore, was confined to the 
intrusive (" productive ") dacites, and tliat elsewhere, where disturbed by minor faults 
and fractui-es, was enclosed mainly in the " inferior " dacites. llie fact that two classes 
of rock are involved in the mass of the vein-bearing dacites, and that these are over- 
lain irregularly by younger barren audesites, also considerably altered, renders the 
structure, as already stated, a particularly complicated one. 

Again, from the hanging-wall of the .Martha reef at the iJGO ft. level throughout 
the whole course of the south-east crosscut, a distance of over 300 ft., broken and 
shattered country exists, with numerous minor faults and slickensided jomt-planes. 
This crosscut was abandoned before the time of survey, and the poor ventilation and 
high temperature prevailing admitted of only a cursory examination. It seems likely 
that this zone of distributive faulting and rock-shattering, which is separated from the 
Martlia lode by a heavy band of pug, is connected with the north-north-east trending 
fault. This fault dislocates in the eastern workings of the Grand Junction Mine the 
George, Royal, Empire, and Grace lodes, and thence probably follows the hanging- 
wall of the Martha. The fact that the rock south-eastward of the Martha in the 
Extended is not gi-eatly altered, and that no quartz veinlets were observed to occur in 
it, leads to the suspicion that it may be the younger barren andesite, but the two 
sections cut and microscopically examined scarcely afforded conclusive evidence on this 
point. The slickensided puggy band on the hanging-wall of the Martha lode is 
identical with that noticeable in the upper levels of the Waihi and Waihi Grand 
Junction mines, where the younger andesite approaches the lode. The theoiy of 
repeated fault-movements along a main line of weakness in the older dacites being 
reflected in the overlying younger andesites is admissible, and would account for the 
wide stretch of shattered rock. 

Veins. — Both the Martha or No. 1 lode and the foot-wall branch of ^>'o. 2 lode, 
extending eastward from the Waihi Grand Junction, have been piospected in the 
Waihi Extended Claim. The Mary lode of the Grand Junction should also be found in 
the undeveloped country north-east of the Xo. 2 lode. 

The Martha lode intersected in the 960 ft. level shows an average width of about 
25 ft., and has been followed about 200 ft. It dips to the southward apparently at 
somewhat lower angles than is usual in the neighbouring claim. In character the 
veinstone resembles that in the easterly workings on this lode in the Grand Junction, 
but is, on the whole, more biecciated and rubbly. Blocks of country involved with the 
white (juartz-calcite veinstone are very conspicuous. Sulpliides ai'e confined to small 
sporadic bunches, generally in the foot-wall poition of the vein, and these occasionalh' 
carry gold and silver. Drifting, however, has disclosed no pay-ore. 

The No. 2 lode, which has been prospected by drifts and rises, varies in width 
from a mere seam to about 12 ft., and is of the same general character as in the Waihi 
Grand Junction. Small lenses and bunches of sulphide f>re were found, especially at 
the 500 ft. and 64.5 ft. levels, but these proved too small to be worked at a piofit. 

Between the 805 ft. and 960 ft. levels this vein diminished greatly in strength, 
and proved very erratic in disposition. Judging by its characteristics at tlie lower 
level, the chances of improvement at still lower horizons are remote. The weakening 
in depth of the foot-wall branches of the Martha, not only in the Extended but through- 
out the field, is a general feature. 

At present the only work in progress is the sinking of the shaft. Sheets of vein- 
stone assaying a few shillings per ton are being met at inteivals in the coarsely 
poiphvritic '' inferior " dacite. A level is to be opened at about tlic 1,110 ft. horizon. 



171 

I'ridc of IVai/ti, Claiiii. 

The I'lide uf Wailii Chiiiu (are;i, iUU acres; owners, the I'lidc of Wailii Gold 
mining Company, Limited, Aucliland) adjoins tlie northern bounchuv of the Waihi 
Extended, and is on the line of strike of tlie Martha lode. 

A small shaft was sunk some years ago, but did not penetrate tiie superficial 
rliyolite. Apart froui this no work has been clone. The value of tliis claim will be 
better gauged from the results attending deeper-level ex])loration on the veins in the 
Waihi Extended. 

Waihi Heefs Conmlidattd Claim. 

The Waihi Keefs Con.solitlated Claim (area, 3UU acres; owners, the Wailii Keefs 
Consolidated Gold-minijig Company, Aucklantl) is situated on the plain to the east- 
ward of the Waihi Extended and Waihi Grand Junction, and north-eastward of the 
Silverton section of the Waihi Company's holding. 

Some years ago intermittent attempts were made to penetiate by shaft-sinking 
and by boring the y<tunger barren rocks — rhyolites and andesites — overlying the older 
dacites, but these eil'orts resulted in failure. Systematic developmental work is, how- 
ever, being undertaken by the present company, which has lecently acquired the 
property. A vertical shaft 13 ft. 8 in. by 6 ft. in the clear is l)eing sunk in the extreme 
western corner of the property, and is equipped witli multitubular boilers, liigersoll- 
Kand air-compressor, steam winding-winch, pumps, Arc. 

The superficial rocks of the claim, underlying the usual weathered debris, are 
the pumiceous tuffs of the rhyolitic series. These have been penetrated in several bore- 
holes. In tlie shaft tiiey were found to persist to a depth of 400 ft., where they were 
underlain by a 20 ft. stratum of loosely compacted conglomerate resting on the 
younger andesite. The shaft, which is now down 700 ft., is still in the latter rock. 
This rock consists of a hoiiiblende-pyroxene andesite, hard, dark-coloured, and rela- 
tively little altered, although slickensided joints, lined with a greenish chloritic 
mineral and films of pyrite, are prominent. Crushed bands showing similar 
mineralization occur here and there. Xo (piartz veins iiave been seen. 

It is the intention of the company, after the older dacites are entered, to sink as 
deep as the giound-water level (determined by the drainage operations of the Waihi 
Comj)any) will permit, and then to drive exploratory crosscuts. Developmental work 
in the eastern part of the Grand Junction Mine will afford some guidance for the 
direction of future prosi)ecting in this claim. 

The Consolidated Claim, it will alrea<ly be realized, appears to lie altogether to 
the eastward of the main mass of the intrusive dacite which exists in the Waihi and 
Waihi Grand Junction mines. It is not improbable, therefore, that veins following, 
like the Silverton, an approximately north-south course — that is, veins lapi)ing 
around the intrusive area, but enclosed in tlie outskirt or intruded country — may be 
just as likely to exist in the Consolidated ground as veins on the strike of the Royal 
and the Empire. 

Other Clnivix. 

Waihi Eomuliis Claims. — Tlie Waihi Hoiiiuliis ground compri.ses three claims, known 
as W^aihi Prince, Wailii Piincess, and Waihi Prince Extended. These claims, wliich 
are owned by local syndicates, are held under a working-option by the Waihi Romulus 
Gold-mining Company, London, and have heretofore never been worked. They lie to 
the eastward of the Pride of Waihi and Waihi Consolidated claims. 

Diamond drilling is now in progress, with the object of locating at a depth tlie 
older vein-bearing dacites, and solely on the results obtained will depend the future 
policy of the Romulus Company. 



172 

It Ks iiuj)obsil)k' ill hazard an tjpiiuoii ais to tliu iluplli to wliicli the younger 
andesites persist in this area. Tliu burelinkci arc near llie base uf andesitic hills ; 

which rise boldly iiom the plain. The andesites may possibly be intrusive at this i 

point, and such a condition would j)! eclude the existence here of the older dacites. •■ 

\\ (iihi Gladstone Claim (area, 30 acres; owners, an Auckland syndicate). — Ihe ' 

Waihi Gladstone Claim is a small block of ground contiguous to the south-east boundary ; 

of the Union-Silverton section of the Waihi Mine. \ 

The total recorded production is as follows : 1900—5, 852 tons crushed for a i 

yield of 703 oz. 12 dwt. bullion, valued at £420 9s. lOd. > 

This propei'ty has been worked only intermittently, and on a small scale. 
Haulage apparatus and a cyanide plant have been erected, but no work is at present : 

in progress. 

The plans show that three veins, striking approximately parallel with the Mascotte 
and Amaranth veins of the Waihi Company's property, exist. On the largest of 
these — No. 3 — drifting has been done over an extent of 700 ft., partly froni an adit 
and partly from a level opened from a shaft at a depth of 100 ft. ■ 

Tlie veinstone of the Gladstone veins differs in no respect from that of the i 

Amaranth and other veins in the adjoining claims. The yield fr(mi the ore treated j 

was low, but it is possible that the treatment methods adopted were unsatisfactory. 



'.,«/»f, , Au-Mmul Liu.d D..-:r, 




?3 QJOO HOfTOHOl, GMASO 



173 



CHAPTER VII. 



SUMMARY OF IHE MINERAL RESOURCES OF THE WAIHI-TAIRUA 

SUBDIVISION. 



Page Page 

(a.) The Present Position and Future Pro- (6.) Mineral Deposits, &c. — continued. 

spects of Gold-Silver Mining 173 St-lenium .. 181 
(6.) Mineral Deposits other than Gold-Silver Coal .. 181 
Veins . . 180 (c.) Stones for Building and Mac- 
Mercury . . . . 180 adamizing . . . . . . 181 

The mineral resources of the Waihi-Tairua Subdivision niaj* be reviewed under the 
following headinf<s : (a.) The present position and future prospects of gold-silver 
raining. (/>.) Mineral deposits other than gold-silver. (r.) Stones for building and 
macadaniizing. 

(«.) The Present Position .^nd Future Prospects of Goi.d-silvkr Mining. 

The Waihi-Tairua Subdivision, Hauraki, has since the earliest discoveries in 1875 
until the end of 1910 yielded from quartz veins gold-silver bullion of an estimated 

value of £10,824,304. The individual mining centres have contributed to this aggregate 

output as follows : — £ 

Waihi . ... ... ... ... ... 9,649,345 

Owliaroa ... ... ... ... 53,714 

Waitekauri - Golden Cross 497,214 

Koinata ... ... ... 41(2,394 

Maratoto ... .. 25,900 

Tairua-Neavesville . . . 130,927 

Whangamata-Whareka^va ... ... ... 46,56^3 

Wharekirauponga . . ... ... . 25 

Ohui ... ... ... ... ... . 497 

Boat Harbour ... ... ... ... 22 

Gumtown . . ... ... ... ... 14,062 

Omahu ... . . 1,800 

Kirikiri ... ... .. ... . 1,696 

Kauaeianga (Hihi Creek only) ... ... .. 145 



£10,824,304 

A feature of the subdivision is the number of isolated and circumscribed areas 
in which mining has in tlie past been conducted or is now in progress. The dis- 
tribution and extent of these metalliferous areas is intimately connected with 
geological structure. It may be here recapitulated that volcanics referable to three 
main periods of Tertiary eruptive activity, designated in order of age the " First," 
"Second," and " Tliird " periods respectively, constitute the rock-complex of the 
subdivision. Hydrothermal action productive of economically important areas of 
metallization appears to have accompanied or succeeded the extrusion of the volcanics 
of the " First " and " Third " periods only. A few relatively unimportant ore-shoots 



174 

have been mined fi-oni veins enclosed in " Second Period " rocks, l)ut tliere is 
considerable evidence that these deposits are connected with the " Tliird Period " 
mineralization. 

The " First Period "' or oldest voleanics — andesites, dacites, and dacitic rhvolites* 
— enclose veins whicli have up to the end of the year 1910 yielded £10,634,558, or 
9<S-24 per cent, of the aggregate output. " Second Period " voleanics — andesites and 
dacites — enclose veins which have yielded £.39,000, or 0.36 per cent. " lliird 
Period " voleanics — rhvolites — enclose veins and mineialized zones which have yielded 
£150,746, or 1-39 per cent. 

In discussing first the possibilities of the discovery of important metallifero^is areas 
a|)art from those already known, and also the chances of the lateral extension of the 
recognized areas, the facts just outlined are of great importance. 

It will be realized that the " First Period " or older voleanics have in this sub- 
division, as elsewhere throughout Hauraki, proved by far the most important vein- 
))earing rocks. A perusal of the maps accompanying this report will show that the 
sum total of the tliree areas throughout which these i-ocks have development at the 
surface does not, in tiiis subdivision, exceed 23' 17 sijuare miles. 

The largest of the three areas, wliich measures about nine miles by two miles 
and a quarter, is that through wliich are distributed the mining camps of Owharoa, 
Waitekauri, Golden Cross, Komata, and Maratoto. While, as indicated later, the dis- 
covery of new prospects is here to be expected as the result of further exploration, it 
IS unlikely that an extension of the auriferous country beyond the limits of the " First 
Period " voleanics will ever be demonstrated. 

■•A smaller area, but one which has proved much more important than that 
mentioned, constitutes the Waihi Goldfield. Considering for the present only the possi- 
bilities of the lateral extension of the field as a whole, it may be stated that an 
examination of the surface gives no clue, as, with the exception of the Martha Hill 
and the Union-Silvevton hills inliers, the vein-bearing rocks lie deeply buried under 
younger barren voleanics. The policy of the various mining companies, excepting the 
Waihi Reefs Consolidated, wliicli company is sinking a shaft in an unexplored locality, 
is evidently to work from the known to the unknown — to extend drifts and prospecting 
crosscuts at the deeper horizons into unexplored country. This course has, at least for 
the present, much to recommend it. 

The Puriri area of " Fiist Period " voleanics, wliich is but the easterly extension 
of an area lying within the Thames Subdivision, is, judging by surface exposures, 
of no great importance. Underlying the Pliocene rhvolites, however, the old voleanics 
extend into the Champion and Golden Belt claims on the main range. Metallization 
in these two claims is, however, genetically connected with the rhyolites. 

Next, as regards the " Second Period " volcanic, wliicli form a large part of the 
subdivision, the prospect of discovering witliin tliese rocks profitable mining country 
is not hopeful. In the older group of this series — andesites and dacites — occur the 
veins worked in the Kirikiri Valley, Wharekawa Valley, Wentworth, or Te Moanuanu 
Valley (Whangamata), Boat Harbour, some of those at Ohui, as well as those of the 
Chelmsford and otlier western branches of the upper Tairua. Tlie occurrences are 
all isolated ones, and most of them are probably genetically connected with the neigh- 
bouring rhyolitic extrusions. None of the mining companies or syndicates which has 
operated on veins enclosed in " Second Period " rocks has reaped any profit. It is 
fairly safe to predict that other localized metalliferous areas will, as the result of 
future prospecting, be discovered in the great stretch of country covered by these 

*[Dacitie rhyolites occur at Owharoa only. 



176 

rocks. Tliere is, howevei-, no loasdii td suppose that tlie veins and ore-di'posits which 
remain undiscovered are niaiivedly dil'feient from tiiose already exploited. Conse- 
(juently tliere is little incentive for tiie exiienditnie of money on prospecting in the 
rocks of this seiies. 

Tlie " Third Period " rocks — rhyolites and dacitic rhyolites and their associated 
tuffs and breccias — enclose tiie ore-deposits of Oniahu, Hihi (Kauaeran<ra), Qumtown, 
Lower Tairua, Pakirarahi Mountain (Xeavesville), Ohui,* Luck-at-Iiast (Wharekawa), 
Wl'.arekirauponga, and Waihi Beach. 'Ilie metalliferous areas of the localities named 
ai'e all isolated, and of relatively snuill extent. Witli the exception of tliose at Gum- 
town, Hihi, and Xeavesville tliey are ])ractically confined to intrusions of massive 
rhyolite. Tlie Lower Tairua area, which includes the 'I'airua Hioken Hills Claim, has 
proved the most important. Lateral extension of any of tiiese vein-l)eaiint!: areas 
heyond their now determined limits is not to he expected, 'i'iie Xeavesville and Gum- 
town fields, as well as the unimportant Hihi prospects, lie mainly or entirely in 
tufaceous rhyolites sliowing locally pronounced alteration. The first-named field is 
prol)al)ly the locus of an old explosion-ci'ater. 

Tlie iliyolitic rocks, as the maps will show, have a great development throughout 
tlie length and l)readth of tiie subdivision. By far the greater extent of this country 
is devoid of quartz veins, but in local areas of hydrothermal alteration there occur 
siliceous sinters, silicified bands, and veins of chalcedonic (piaitz. Tlie detailed suivey 
of the wiiters, however, failed to locate metalliferous rhyolitic areas w<u'thy of note 
beyond the confines of those that have alrea<ly claimed the attention of the prospector 
and miner. 

Regarding the future of mining in the sulidivision, it will be gatliered from the 
foregoing that the various areas or belts of country which iiave yielded the gold of 
the past ai'e those destined to afford the gold of the futiiic. Discoveries of importance 
are only to be expected in or near those localities whicii have yielded profitable ore — 
that is, within the belts of tlie older (" First Period ") volcanics and the few recog- 
nized mining areas in the younger rocks. Here history is likely to repeat itself, and 
further veins and ore-shoots may from time to time be unearthed. 

The actual surface of these ascertained auriferfuis areas has been time and again 
searched by tlie prospectoi- and the digger. It siiould lie stated, however, that a heavy 
oveiiiiantle of debris and a den.se forest undergrowth covers almost the whole of this 
Country, and rock-exposures, except in the watercourses, are few an(T far between. 
The greater part of the area so covered has baffled the piospector and the digger. 
This ground is still available, but it is evident that more systematic and extensive 
operations will be required for its future successful exploration. In the " back 
country " very little systematic prospecting is at present in ])rogress, and therefore 
the discovery f)f further auriferous veins, lU' of new ore-shoots in known veins, is 
largely a matter of chance. 

The individual mining enterprises of the subdivision, with the exception of the 
Waihi, Waihi Grand Junction, and Komata Reefs, all fall within the category of 
" prospects " rather than mines. 

Some of the prospecting companies are doing exploratifm-work in claims which 
have afforded payable ore-shoots in former days; otheis are continuing operations in 
ground which nevei has proved ])rofital)le, but which affoids spoiadic bunches of ore, 
suggesting the possibility of payable .shoots existing in the vicinity. Only two or 
three companies are dealing with new prospects. The value of all these concerns is 
purely speculative, llieir present positions are set forth in the detailed descriptions. 



* Some of the veins at Ohui are " Second Period " andesites. 



176 

Of the outlying areas, Lower Tairua is at present claiming most attention. 
Within the Tairua Broken Hills Claim the veins crossing the auriferous zone in the 
rhyolites promise to yield further ore on the downward continuation of some of the 
shoots. On the main adit level there is also scope for further exploration. The Tairua 
Golden Hills and the Tairua Monaich are relatively new prospects. Shoots of low- 
grade oi-e have been developed, and, providing that working-costs can be materially 
reduced, there is a )easonable chance of mining on these claims being conducted at a 
profit. 

At Olmi prospecting in the Phoenix Claim has proved the existence of streaks of 
sulphide ore within a wide band of silicified rhyolite. Systematic exploration at 
greater depths can alone determine whether or not ore exists in profitable quantities, 
and the judicious expenditure of capital in this direction may be regarded as a 
legitimate piospecting venture. 

At Neavesville the Ajax reef of the Golden Belt Claim and one or two pipe-like 
deposits within the Champion Claim proved in tlie superficial horizons the principal 
producers. The reef named continues to afford small lenses of ore at the lowest adit, 
but mining at present is being conducted at a loss. Otlier leefs on which little or no 
exph)ration has been done are known to exist in this area. Furthermore, highly 
silicified rhyolitic tuffs occur as extensive belts or sheets (" The Bluffs ") within the 
Golden Belt Claim, and as zones or bands (" dykes ") in the Champion Claim. These 
silicified tuff's are auriferous, and unsuccessful attempts have been made to work 
certain portions as low-grade ores. The writers liave been unable to ascertain the 
actual value of the bulk material treated. It is stated, however, that a huge tonnage 
which assays 10s. per ton in gold-silver exists. If this statement be correct, these 
deposits, whicli admit of open quarrying, may at some future time prove of economic 
importance. 

Within the belt of " First Period '" volcanics extending from Owharoa to Maratoto 
the veins of its southern portion — namely, Maratoto, Komata, Golden Cross, and 
Upper Waitekauri — are all of the same type, mainly quartzose replacements after 
calcite. Wherever the occurrence of ore-shoots has led to these veins being followed 
downward, calcite has been found to become more and more prominent with increasing 
depth. Finally, not only the ore, but the low-grade or barren quartz has practically 
vanished, the fissure-filling here consisting almost altogether of calcite. Only at 
Golden Cross was an attempt made to determine the conditions which exist below 
where the barren horizon appeared. Here four boreholes were sunk. As these holes, 
it is stated, failed to locate even the vein fissure, they have afforded no data which 
are applicable to the field in general. It will at some future date probably devolve 
upon the financially strong companies at Waihi, where the genesis of the veins is 
similar, to settle by deep-level exploration this question. 

At Maratoto the exploration conducted by the Hikutaia Gold Syndicate demon- 
.strated the existence of a large tonnage of veinstone assaying about 15s. per ton. 
This ore, although very low grade, may eventually be made to yield a profit. In the 
Silverstream Claim driving is in progress at the lowe.st adit practicable, with the 
object of intersecting certain veins ■which at shallower horizons carried small shoots 
of fairly rich silver-ore. 

At Golden Cross Claim the present owners have made no attempt to unwater the 
mine abandoned by the Waitekauri Company. Attention is confined to certain blocks 
of low-grade ore available at the adits, and a ten-stamp mill with a cyanide 
plant, to be operated by water-power, is being erected. The main Golden Cross reef 
strikes in the direction of Komata, and between the two localities little prospecting 
has been done. 



177 

In the Koinata Reefs Claim the lower portions of the ore-shoots, the strongest of 
which had a vertical range of about 800 ft., are being worked. Ore to the amount of 
10,880 tons was milled in 1910 for a yield of £1 18s. 4d. per ton. This yield was 
little moi-e than sutiicient to meet working and general expenses. The ore-reserve at 
the end of 1010 was estimated at l:i, ()()() slinit tons. Furthi-i- exploratory woi'k at the 
existing levels is being done. Winzinir bthnv tlie lowest adit, however, has revealed only 
barren calcific vein-filling. 

At Lower Waitekaiiri, formerly the scene of considerable mining activity, there 
are now only three working prospects — namely, the Jubilee, Scotia, and Maoriland. 

In the Jubilee the main Waitckauri reef is being further prospected in a small 
way, and short stretches at tlie lowest adit liave shown sulphide ore worth, it is stated, 
from £2 to £.3 per ton. The capital at present being expended in adit-level pro- 
specting might, with advantage, be diverted to drilling several boreholes so as to explore 
the big reef at greater depths. 

The very small area (about 9 acres) which formerly constituted the Jubilee 
Hill holding of the Waitekauri Gold-mining Company (Limited) debarred this 
relatively strong company from undertaking much systematic prospecting away from 
the main reef. Having regard to tln> loose blocks of auriferous veinstone reported to 
occur in the subsoils of the lower giound skirting this hill, and the existence of veins 
carrying .small ore-shoots in the Scotia an<l other claims, a low-level adit crosscut 
here would have offered a better prospect than some of tlie long crosscuts diiven in 
other parts of Waitekauri Valley. 

At Owharoa the deposits of the old Smile-of-Fortune Claim, which yielded the 
greater part of the oie mined from tiiis distiict, were of the stock-work type, lliese 
graded into more definite sheeted zones or veins when followed in depth, l)ut here 
proved unprofitable. The Rising Sun Company is exploring one or moic fairly well- 
defined quartz veins, and the low level now l)eing driven will determine tlie persistence 
and value of the known ore-shoot. From tliis level further exploratoiy work will 
probably lie undertaken. 

The main hopes for the future of mining in the subdivision naturally centre al)out 
Waihi, which has yielded no less than 89 per cent, of the total value of the metal-output. 
The geological structure of the Waihi fJoldfield, as deciphered by the writers, 
leads to the conclusion that tlie more productive country is confined to the locality 
and immediate environment of a dacitic intrusion, which measures at the 1,000 ft. 
level about 50 chains by 20 chains. Notwithstanding the fact that rich ore has 
been mined from sliallow hi>rizons in the I'nion-Silverton hills, it would appear 
reasonable to infer tiiat the further developmental work is extended beyond the limits 
of the main dacitic intrusion (which encloses the greater part of .\iartlia-Edward, 
Empire. Royal, and otlier veins), the less favourable is the prospect of profitable ores 
being discovered. The possibility, however, that other similar dacitic intrusions occur 
in the unexplored deeply buried area of the older volcanics must be conceded. If 
future explorations should reveal the existence of such intrusions, the potentialities of 
the lateial extension of the Waihi field would be niaterially im])roved. 

Beyond the limits of the main dacitic intrusion developmental work now in pro- 
gress in the easterly end of the field, in the Grand Junction, the Wailii Extended, 
and Waihi Reefs Consolidated claims, will throw considerable light on future pro.spects 
in this direction. To the southward and south-eastward the exploratory cro.sscuts 
being driven by the Waihi Company are also penetrating unknown country. To the 
northward the fact that the Waihi Company's boundary lies only 11 chains from the 
Martha lode has restiicted the amount of crosscutting and boring ilone in country on 
12— Waihi-Tairua. 



178 

tlie " hack to hack "' line of tlie main ore-shoots. Although this country is beyond 
the limits of tlie intrusive or " productive " dacite, a pi-ospecting chance must be 
conceded to its une.\i>Ioied portion as far as the older dacites may be found to persist. 
To the west of Martlia Hill reliable data regarding structure are meagre. It would 
appeal' from boring-records that a deep valley filled with younger andesite exists. 
Traversing an old buried spur or hill-flank bordering this valley the westerly exten- 
sion of the Welcome lode lias been traced for about 300 ft. A weakening of this 
Welcome vein in depth is here to he expected, and, as indicated elsewhere, the 
westerly extension of the Martha-Edward lode (designated tlie Royal in the Waihi 
Company's reports) may be found to be the most persistent of the known vein fissures. 

Reference should be made to evidences of mineralization in outlying country on 
the approximate easterly line of strike of the Martha vein-system, wliicli have led to 
the staking of mining claims at various times. In the old Waihi Mi>nument Claim, 
at a point three miles east of the Waihi Grand Junction, a thermal deposit of 
siliceous sinter and massive iron-sulphide occurs near the contact of " Second 
Period " andesites and " Third Period " i-hyolites. Further eastward about 
160 chains, and on the actual coast-line, a silicified band exi.sts in intrusive 
rliyolites. A little prospecting-work has been done in each locality. The gold-silver 
content of both formations is, however, very low, even the iron-pyrite of the first- 
named carrying only 9 gr. of gold and 1 dwt. 12 gr. of silver per ton. Certain 
optimists have assumed that the occurrences named are the easterly extensions of the 
Martha vein-system, but as they are both associated with rocks eriipted since the 
formation of the Martha veins this assumption is quite erroneous. 

With all due regard to the restdts which may attend prospecting-work at Waihi 
in the directions indicated, it is probable that by far the greater bidk of the gold- 
silver yield will be derived from the lodes lying within or near the intrusive 
(" productive ") dacite. The ore-reserve at the clo.se of 1910 was assessed at 
1,801,931 tons (Waihi Company, 1,669,031* tons; Waihi Grand Junction Company, 
132,900 tons), and these figures have been augmented by subsequent developmental 
work at the lowest level in each mine (No. 9 Waihi, No 5 Junction). As the former 
company is at present milling about 320,000 tons and the latter 100,000 tons per 
annum, the time required to exhaust the ores blocked is relatively sliort. A great 
deal therefore depends upon the persistence of the pay-shoots in depth. 

In the Waihi Mine each successive level down to No. 8 (850 ft) exposed, on the 
whole, an increased amount of ore compared with the level above. Level No. 8 has 
proved the best yet opened. The developmental work at No. 9 (1,003 ft.) level has 
revealed considerably less ore than existed at No. 8. The tables compiled from the 
official reports, taking both tonnage and values into consideration, show a falling-oS 
between these two horizons of approximately 01 per cent. On the whole, at No. 9 
level the quantity rather than the quality of the actual ore has diminished, but in 
many places the whole stoping-width is rendered low grade owing to the streaks of 
ore being scattered throughout a considerable mass of poor veinstone. 

In the Waihi Grand Junction Mine the vein-bearing rocks lie beneath the bed of 
an old depressed valley filled with barren volcanics. Furthermore, the original apices 
or caps of the veins were, in most cases, found intact. Although, therefore, the 
lowest level is opened at a depth of 944 ft. from the surface (25 ft. above the Waihi 
Company's 1,003 ft. level), the backs available on the various veins have been found 
to range only from 550 ft. in the case of the Martha lode down to 30 ft. or 40 ft. in 
the case of the Royal lode. Throughout a given horizon, therefore, conditions in 



* Includes 600,697 tons forming arches, pillars, &e. 



179 

these two adjoining mines are not comparable. IJoth tlie Empiie and Royal lodes, 
which in the Wailii Mine iiave shown impoverishment at the No. 9 compared with the 
No. 8 level, have in the Grand Junction exhibited considerable improvement between 
the same or nearly corresponding levels. As an ore-producer tlie Martha lode in the 
Grand Junction has .so far not fulfilled expectations, tiie great slioot worked in the 
Wailii Mine having been found to have no extension into this property. A stretch 
of 300 ft. of barren or low-grade veinstone intervenes in the Waihi Mine between 
the eastern limits of this steeply i)itc]iing shoot and the Ixmndary of the claims. The 
shoots worked on this lode in the (irand Junction have been relatively small and 
pooi'ly defined, and, furthermore, have less development at the lowest level opened 
(No. 5) than at shallower horizons. Having i-egaid to tlic probable encroaclimeiit in 
depth of the bedded (" inferior ") dacites on to the foot-wall of the Martha, aii\- new 
shoots of ore which future developmental work below No. ") level may leveal are (piite 
as likely to be associated with the hanging-wall side as with tiu' foot-wall si(K' of this 
large vein. 

At Waihi, as in many Tertiarv goldfields, the deposition of the (U'es has taken 
place comparatively near the surface. It may \k- assumed tliat during the peiiod 
of ore-deposition the metal-ljearing solutions rising in the fissures were hot, and that 
the gi'adient of falling temperature over a given vertical range was much more pro- 
nounced neai' the surface than at tlie deeper horizons. Falling temperature and al.so 
decrease of jiressure favoui- precipitation. 

The genesis of the Waihi ores is lather an unusual one. In all othei' places where 
veins of strictly the same type as those of Waihi have l)een worked in Hauraki — 
namely, at Komata, Golden Cross, and Maratoto — the vertical lange of the ore-shoots 
has proved small. At Komata the greatest vertical range of a shoot 700 ft. long was 
less than 800 ft.; and at GoMen Cross, where the principal shoot luul a maximum 
stops-length of 760 ft., tlie vertical range was alxmt oOO ft. At the lowest levels 
opened in these two h)calities the ore, and even the unprofitable quartzose veinstone, 
which is in great part a replacement after calcite, was found to give place to the 
barren parent calcite. It should, however, be stated that the ore-shoots at the 
localities named were smaller in stope-lengtli and cross-section than the main shoots 
of the Waihi field, and, furthermore, that at Komata, and to even a greater extent at 
Golden Cross, erosion had laid bare the veins and planed off an uidvnown amount of 
the ore-shoots. 

As far as the writers are aware, three other mining fields regarding which 
literature is available present ores closely analogous to the Waihi and neighbouring 
camps mentioned. These are De Lamar (Maho) and Gold Hill (Piute Country, 
Utah), in the United States of America; and Redjang Lebong, in Sumatra. In the 
De Lamar and Oro Finu mines*, at De Lamar, the veins continued strong and well 
defined when followed in deptii No considerable shoots, however, have been developed 
lielow a depth of 600 ft. from the outcrops in the former mine ami below a depth of 
900 ft. or 1,000 ft. in the latter. Alth<.ugh tiie (piartz is largely pseudomorphous after 
calcite, the zone of the carbonate had apparently not been reached. 

Concerning the Annie Laurie Mine (Gold Hill), Lindgren writes: "The Annie 
Laurie, as to country rock, ore, and stiucture, is an almost exact counterpart of the 
Waihi deposits of New Zealand, though it does not possess the great number of veins 
nor the enormous amount of ore exhiluted by the latter bonanza. "t 



*20th Annual Report U.S. Geol. Sur. (Lind<,Ten. W.). pp. 107-88. 
+ Bull. U.S. Geol. Sur.. No. 285. 1906. p. 87 



12 •— Waihi-Tairua. 



180 

The verticil range opened on ore ;it the time the above was written (year 1 !)()()) 
was ahont 800 ft. To what extent the shoots were subsequently followed the writers 
have been unable to asceitain. '1 he mine is now closed. 

In tlie Redjang Lebong Mine the main ore-body measures about 9r)0 ft. in length 
and up to 62 ft. in width. It outcropped at the surface, which here has an elevation 
of about 1,300 ft. The ore-shoot has been worked to a depth of 4.30 ft. from the 
outcrop, and here (No. 4 level) wliat is regarded as a comparatively poor zone has been 
disclosed. The No. 5 level, about 78 ft. below No. 4, is being opened.* 

In considering low-level conditions at Waihi reference is frequently made to the 
Talisman Mine at Karangahake, eight miles from Waihi. Profitable ore has been 
mined from the Talisman vein through a range of 1,800 ft., and the lowest level 
(No. 13) is 270 ft. below sea-level. Furthermore, when followed in depth the ore has 
been found to be disposed in zones or floors separated by unproductive zones. It 
may be stated that the Talisman ores are not strictly comparable on the score of 
genesis with those of Waihi ; and, again, the zonal disposition of profitable and 
unprofitable veinstone is apparently due to local structural features. The poor zone 
observed by the wiiters during a cursory examination of the Talisman vein was found 
to be coincident with the locality of a marked flattening of the vein fissure. Minor 
differential movement or faulting along the plane of the vein led to a material closing 
of the vein fissure in these flat-lying portions — a condition which has been unfavour- 
able to ore-deposition. 

At Waihi tlie quantity of veinstone, irre.spective of its value, has been and pro- 
mises to be well maintained in depth. The chances, however, of ore existing below 
a non-productive zone are dependent upon marked fluctuations having occurred in 
volume, velocity, and temperature of the ascending ore-bearing solutions. Such 
fluctuations, simulating the action of intermittent hot springs, have on certain fields 
been held to account for the zone or " critical levels " at which ore has been deposited. 

In conclusion, it may be remarked that thei-e is in the writers' opinion consider- 
able justification for the statement regarding the future prospects of the Waihi Mine 
that appeared in a special report incorporated with the Proprietary Company's annual 
report for 1010. Mr. R. E. Williams, Assistant Superintendent, here remarks: "I 
have every confidence that good makes of ore will be found in this mine, but I believe 
the ore will be found more and more in lenses or bunches. I am doubtful if such long 
and continuous shoots of ore will be found in the lower levels as existed above the 
1,000 ft. level." 

The Grand Junction Mine, as the sectional plans accompanying tliis bulletin will 
indicate, is a deeper-level property than the greater part of the Martha section of the 
Waihi Mine, and, as already remarked, conditions at the same horizon throughout 
these adjoining properties are not conq:)aralile. The apices of the veins being related 
to the contours of the older volcanics, the ores may be expected to persist to greater 
depths from the existing surface m the Waihi Grand Junction than in the Waihi. 

(h.) .Mineral Deposits other than Gold-Silver Veins. 

Mercurj/. — Mercury is tlie only metal other than gold and silver which has been 
mined in tlie subdivision, if the trifling amount of lead and zinc contained in 
auriferous concentrates shipped in tlie earlier years of mining be excepted. Small 
quantities of cinnabar, derived from deposits in siliceous sinters at Mackaytown, and 
of mercury locally extracted from the ore have been exported during the past year or 
two. So far developmental work here has revealed only relatively small quantities of 
ore. Further explorations are in progress. 



* Annual Report of the Propy. Coy., dated December, 1910. 



Per Cent. 


30-40 


30-38 


17- 08 


21-64 



181 

t>tlttuuiit. — Seleiiiiini, a min-iiiL't:i!Iiu mineral, has been obtainud in small niiantity 
as a by-pio(luot bv the \\ aihi Company in tlie letiuing of gold-silver bullion. 

Coal. — Discoveries of coal within the subdivision have from time to time been 
reported, lliese occurrences are all connected with the unconformity sediments which 
in places separate the volcanic rocks of diffeient ages, and, as regards disposition, 
partake of all the irregularities of these old land-surfaces. 

The greatest development of carbonaceous shales and associated seams of impure 
coal are to be found in the valleys of Tarariki [Takerei] and certain other creeks 
draining th(,' iiilly country between Mackaytown and Paeroa. Tliese lie at the base of 
the younger Beeson's Island andesites. An analysis* of oal from the main car- 
bonaceous band in Tarariki Creek is as follows : — 

Fixed carbon 
Volatile hydrocarbon 
Water 
Ash 

10000 
Owing to the iiigh percentage of ash in all these coals, and the irregularity of 
the seams, the occurrences can have Init little economic value e.vcept, jjcrhaps, for 
limited u.^e if required in the near vicinity of their outcrops. 

(c.) Stones fou Bi'ii.dini; and M.acadamizing. 

The andesites thrf)Ughout the area are so closely and irregularly jointed that even 
the hard and unaltered rock is unsuitable for building-stone. Furthermore, andesitic 
rocks in general are noted for tlieir lack of rift, dressing being thus rendered Ixith 
difficult and expensive. 

Certain of the rhyolitcs — the brecciated flow rock (wilsonite) and the compact 
tridymitebearing variety occurring in the neighbourhood — are suitable for use as 
building-stones. Both tliese rocks have been used by the mining companies in construc- 
tional works where strength and durability are essential. If carefully selected, the 
wilsonite should afford a .suitable and not unattractive building-stone. 

For macadamizing roads, the hani unaltered andesite — " blue metal " — is the 
rock generally used throughout the di.strict. Suitable rfick is fairly abundant, but 
the locality of an outcrop is the main factor in assessing its value. The softer 
rhyolitic rocks arc, at VVaihi and elsewhere, also used in road-construction. 

* Hy Mr. R. .J. .Morgan. 



183 



INDEX 



A. 



Abbott (prospector), 92. 

Acidic igneous rocks (see Rhyolites). 

Acknowledgments, 4. 

Adams, H. H., 77. 

Adams, J. H., (5. 

Adits, minijig from, «.">, 72, 84, 8!), itl. !)2. 102. 115. 

AtUilaria (-ice Valencianite), i;5.5. 

/Eolian tlejiosits, 49, 50, 124. 

Aerial trams, 74, 81, 84, 99, 100, 104. I()2. 

Age of the different rock-groups, 35, '.Hi. 37, 38, 39, 
43, 4(5. 50. 

Agglomerates (■■ict Andesitic and dacitic agglo- 
merates), 3(i, 39, 43, 4t), 47. 

Aiyiiilli topography, 30. 

Air-compre.ssors, 18, 1()2. 171. 

Ait ken, R. M., 0. 

Aja.\ reef, Neavesville, 85, 87, 17K. 

Alabaster, quartz resembling, 107, 138. 

Albert lode, Waihi, 129. 14(1. 

Alderman Islands. 31. 

Ale.xandra lode, Waihi, 129, I4(i. 151. 1.52. 

Alluvial flats, 1, 28, 29. 

Alluvium, 49. .'>0. 59. 

Al[)ha Claim, Waitekauri, 112. 

Alpine Creek, .Maratoto. 104. 

Alteration of rocks {.ipe Meta.somatic re|)lacement, 
Pro|)vliti/,ati()n, Pyritization, .Silicitication), 37, 
53, 54-56. 

Amalgamation of gold, 10, 81, 8G, 101. loii, 144. 

Amaranth Claim, Waihi, 10, 132. 

.Vmaraiith Hill. Waihi. l.")8. 

Amaranth lode, Waihi, 11, 129, 1.58, UiO, 172. 
Analysis of coal. 181. 

Analyses of minerals, 54, 57, 58, 106, 138, 139. 
Analyses of ores, 22, .58, 1.35, 131). 137. 139. 140. l.')9. 
Analyses of rocks, 42, 45, 48, 55. 
Analy.sis of siliceous sinter, 61. 
Analyses of waters, 33, 69, 70. 
Ande'.sinc, 41, 48, 158. 

.4ndesites and andesitic rocks (nee Augite, Horn- 
blende. Hvpersthene and Pvro.xene andesitcs), 
3, 27, .36, 37, .39-43, .5.5, 61. 67, 181. 
Andesitcs of " First Period," 27, 36, 37, 39, 40, 41, 

174. 
Andesitcs of "Second Period." 43— l(i, 124, 125. 
Andesitcs, intrusive, 46, 72. 105, 12.5-26. 
Andesitcs, petrology of, 40-41, 44-i5, 46. 49. 
Andesitic agglomerates, 36, 37, .39, 41, 43. 
Andesitic breccias, 36, 37, .39, 43, 102, 113, 12(i. 127. 
Andesitic tuffs, 36, 37. 39, 43. 116. 125, 127. 
Annie Laurie Mine, (UM Hill. I'tah, U.,S.A., 179. 
Apices of lodes and ore-shoots, 62, 126, 127, 128, 

1.32, 141, 142, 147, 151, 153, 165-167, 178, 180. 
Arbitration Court, 26. 

Argentiferous ore, 13, 14, .52, 9t). 1(X), 102, 103. 
Argentite. 13, .59, 61, 90, 94, 9(), 97, 101, 103, 107. 

114. 119, 134, 136, 139, 143, 150, 1.59. 
Argillite, 38, 124. 
Arizona Creek, .Maratoto, 104. 
Aroha Subdivision, 1. 
Arsenopyrite, .59. 

Ascot Cinnabar Mine, Mackaytown, .59, 119-121. 
Auckland, 123. 

Auckland Claim. Whangamata, 01. 9.5—96. 
Auckland Gold-mining Company, 95. 



Augite, 41, 48. 

Augite andesitc, 40, 45. 

"Auriferous series," 39, 40, 63, 124, 127. 

Autodasts. 40, 112. 

Azurite, 59. 



B. 



'■ Hack to back ' arrangement of ore-shoots, 64, 
79, 107, 178. 

Balback tilting furnace, 21. 

Banded ore. Waihi, 1.35, 1.36, 139, 141, 1.52, 16.5. 

Banded rhyolitc, 5(). 

Barrier-beaches. 30, 31. 

Basement rocks. 35, 38, 124. 

Battery {.ict- Milling-practice). 

Battery adit, (Jolden Cross Mine, 109. 

Beaches, 30, 31, .50. 

Beaches, raise<l, 29, 30, 50. 

Beach Slide, Thames, 51. 

Bedded dacites (see " Inferior dacitos "). 

Beeson's Island Series (.ice " Second Period," &c.), 
36, 37. 40, 43-4(i, 105. 181. 

BeiUrhiniedid tuniriri, 2. 

BeiUchmiedia tnwu, 2. 

Beleinnites, sp., 38. 

Bell, .1. M., 4, 6. 

Berdans, 10, 72, 74, 82, 92. 

Big Beetle Claim, (Jumtown, 72, 74. 

Big Beetle (Jold-mining Company, 74. 

Big Blow, .Mackaytown. 120. 

Big Blow, Waitekauri, 8. 

Billy-goat Creek. 32. 49. 

Biotite. 41, 47. 48. I2(). 

Biotite rhyolitc. 72, 74. 89. 90. 93, 12.5. 

Black Hill, Waihi, 49, 123. 124. 12.5, 127. 128. 

Black jack (zinc-blendo), .56, .59, 63, 134, 136. 

Black .sand, 76. 

Blake rock -breakers, 92, 106. 

Bleazanl, — , 8. 

Bleichert aerial tram. 162. 

Blucher r(M'f. Lower Tairua, 77, 78, 79. 

Blue carbonate of co|)p(!r (azurite), .59. 

Blue vitriol (chalcanthite), 59. 

Bluffs, The, N(!avesville, 8r)-86, 176. 

Bonanzas, 7, 16, 179. 

Bonny Scotland Claim, Neavesville, 84. 

Boom, mining, Ki, 17, 24, 88. 

Boreholes (.tie Diamond-drilling), III. 1()8, 169 

171, 172. 
Boss, igncou.s, 53, 125. 129. 132, 140. 
Bowentown beach, .50. 
Bramhall, H., 4. 
Breccia, volcanic (see Andesitic, Dacitic, and Khyo- 

litic breccias), 39, 43, 44, 46, 47. 
Brecciated zones, .52, 77, 83, 90, 97. 
Britannia reef, Neavesville, 85. 

Broken Hills, Tairua, 28, .52, 5.3, 61. 62, ()7, 76-81. 
Bromley, A. H., 5. 
Brown, — , 8. 

Brown and .McMicken slime-agitators, 106, 
Bullion, 59, 139, 181. 
Bulls Run, (iumtown, 74. 
Burbank Claim, Komata, 105, 
Burning of forests, 1 , 2. 
Butler's vein, Waitekauri. 113-14. 
Byron Bay Claim, Komata, 13 



184 



C. 



Cabbage Bay, Coromandel, 118. 

Cadell, H. M., .5. 

Cadmaii Claim, Owharoa, 117. 

Cage, shaft, 19. 

Calcite {see Manganiferous calcite, Quartz pseudo- 

moriihous after calcite), 53, 56, 60, 134, 139. 
Calritic veinstone. 14, 60, 66, 102, 107, 108, 111. 

133, 138, 164, 170, 176, 179. 
Cambria lode, Thames, 167. 
Camoola Claim, Jlaratoto, 102. 
Camoola Creek, Maratoto, 103. 
Camoola reef, Maratoto, 102, 103. 
Campbell, J., 5. 

Campbell and Ehrenfried Company (Limited), 33. 
Capital of mining companies, 25. 
Carbonaceous seams, 27, 36, 43, 46, 125, 126, 132, 

148, 187. 
Carbonates {see Azurite, Calcite, Malachite, Man- 
ganiferous calcite, Rhodocrosite, and Siderite). 
Carbonates, origin of, 53-54. 
Carbon-dioxide, 54, 65, 66, 67. 
Carboniferous rocks, supposed, 38. 
Cassel's Company. Waihi, 143. 
Caves, 30, 110. 111. 
Caves, The, Lower Tairua, 77, 78. 
Chaleanthite, 59. 
Chalcedony and chalcedonic cjuartz. 56. 78, 87, 97, 

138, 17.5. 
ChalcopjTite, 56. 59. 61, 62, 114. 115, 134, 136, 

159. 
Challenge ore-feeders, 106. 
Chalybeate waters, 33. 
Champion Claim, NeavesviUe, 61, 63, 84, 86-87, 

98, 174, 177. 
Champion Gold-mining Company (Limited), 15. 
Champion Mines (Limited), Auckland, 86. 
Champion reef, NeavesviUe, 86. 
Charcoal in volcanic rocks, 48. 
Chelmsford Claim, NeavesviUe, 84, 87-88. 
Chelmsford Creek, NeavesviUe, 87. 
Chelmsford Gold-minmg Company, Auckland, 15, 

87. 
Chemical analyses {see Analyses). 
Chert, 55. 

Chert Creek, NeavesviUe, 87. 
Chlorite, 40, 54, 57. 

Chkjritic alteration. 41, 45, .54, 55, 63, 96. 
Christie's vein, Waitekauri, 113. 
Cinnabar, 18, 59, 62, 119. 120, 121, 180. 
City of Glasgow Claim. Owharoa, 117. 
Cliff -retreat, 31, 32. 
Climate, 2, 28. 

Coal-seams and coaly partings, 27. 36, 43. 46, 181. 
Cobalt, 110, 139. 
Collins Creek, Tairua River, 32. 
Communication, means of, 3. 
Companies, gold-mining, 25. 
Compressors, air, 18, 162, 171. 
Concentrates, 136, 137, 144. 
Cones, volcanic, 36. 

Conglomerate, 27, 67, 69, 124, 127, 171. 
Conjugate fissures, 53, 128. 
Conqueror Claim, Tairua Broken Hills. 82. 
Contract, payment by, 26. 
Copper-plate amalgamation, 10. 
Corbett, — , 10. 

Corbett"s level. Golden Cross Mine, 1()9. 
Corbett's reef, Maratoto, 102, 103. 
Cornish pumps, 18, 143, 144. 
Coromandel, 7, 16, 127, 141. 
Coromandel Subdivision. 1. 36, 38, 40, .53, 118. 
Coronation Claim, Tairua Broken Hills, 82, 83. 
Correlation of rocks, 36, 37, 38, 43—44. 
Costs, mining, 26. 



Coulter, W. H., 4. 

Cox, S. H.. 4. 

Craters, 36, 39, 63, 86, 89, 127, 128, 175. 

Cripple Creek, Colorado, U.S.A., 3. 

Critical level of ore-deposition, 142, 180. 

Croat ians, 2. 

Cross-courses, cross-fissures, 64, 67, 73. 

Crown land, 24. 

Cyanide process of gold-extraction, 9, 11, 13, 21. 

22, 23, 24, 101, 123, 139. 
Cyanide plants, 72, 77, 81, 82, 84, 87, 92, 95, 99, 

104, 106, 108, 112, 113, 116, 144, 162, 172, 176. 
Culpan's Creek, Wharekawa, 93. 
Customs mills, failure of, 26. 



D. 



Dacite and dacitic rocks {see Inferior dacites, Pro- 
ductive dacites), 3, 27, 36, 37, 39, 40-47, 49, 54, 
55, 124, 12.5. 

Dacite, analj'ses of, 42, 55. 

Dacite of " First Period," 27, 36, 37, 39, 40, 41, 49, 
124, 125. 

Dacite of " Second Period," 27, 36, 37. 43—16. 

Dacite of " Third Period," 36, 37, 46, 47. 

Dacite, petrology of, 40, 41, 44, 45, 47. 54, 55. 

Dacite-rhyolite,"36, 39, 41, 114, 117, 118, 174, 175. 

Dacitic agglomerates, breccias, and tuffs, 36, 37, 39, 
43, 105, 116, 117. 

Davey's reef, Tairua Broken Hills, 81. 

Decitle Claim, NeavesviUe, 84. 

Decrease of ore in depth, 16, 61, 64, 65, 66, 81. 

De Lamar Mine, Idaho, U.S.A., 179. 

Depth of ore, 61, 64, 65, 66, 81. 

Depression of land, 27, 28, 32. 50, 51. 

Development of mines, cost of, 26. 

Devonian rocks, supposed, 38. 

Diamond-drilling, 25, 111, 115, 116, 171. 

Dissection of land-surface, 27, 32, 36, 65. 

Distribution of the various rock-groups, 39, 40. 45, 
46, 47, 49, 50, 124, 125. 

Dominion Analyst and Laboratory, 4, 33. 

Don, J. R., 5. 

Donnelly's Creek, Waitekauri, 109. 

Dore refining plant, 145. 

Dorr slime-thickener, 106. 

Drainage-channels, 1, 29, 30, 32, 68. 

Drainage of mines, 11, 12, 18. 

Dreadnought Claim, Maratoto, 103. 

Dreadnought Claim, Ohui, 89, 91. 

" Droppers," 64. 

Dunes, 50. 

Durbar Claim, Waitekauri, 108, 112-113. 

Durbar Company, 112. 

Durbar Trig., if 2, 113. 

Dykes, 3, 27, 28, 36-38, 49. 



E. 



Earth-movements, 28, 37, 47, 50-51, 52. 
Earthquake shocks, 53, 130. 
Edmond's Creek, Wharekirauponga, 59, 97, 98. 
Edward lode. Waihi, 128, 130, 141, 142. 146, 152, 

156. 
Electric fans, hoists, pumps, &c., 18, 19, 21. 
Electrum, 58. 64, 86, 94, 98, 107, 114, 139, 140. 
Elevation of land, 50, 51. 
ElUot's tunnel, Owharoa, 118. 
Empire lode, Waihi, 53, 55, 64, 127-130, 132, 133, 

141, 142, 1.32, 1.35, 157, 158, 161, 163, 164-167, 

170, 171, 177, 179. 



185 



En!]>ire lode, Waitekauri, 110. 

English conipanies, 17, 25. 

Enrichment of ores, 62, 65, 73, 96, 99, 117, 141, 

142, 143. 
Eocene, 37. 
Epsomite, 56. 
Excellent Claim, Maratoto, 103. 



F. 

Farming, 2. 

Faulting, 28, 29, 47. 50-51, 53, 132, 141. 

Faults, 18, 37, 51, 64, 120, 122, 127, 163, 165, 167, 

170. 
Favona-Brilliant Gold-mining Company, 25. 
Feldspar (nee the various species). 
Felsite, 38. 

Fifth Branch of Tairua River, 87, 88. 
Filling of stopcs, 19, 20, 21, 145. 
Financial conditions, 24—26. 
Finlayson, A. M., 6, 40. 42, 54, 55, 57. 
First period of volcanic activity, 3, 27, 30, 36, 37, 

39^2, 44, 49, 52, 54, 124-125, 173, 174, 176. 
Firth of Thames, 51. 
Fishing, 2. 
Fissures, tissuring, 52-53, 64, 67, 72, 77. 78, 12U- 

132, 134, 141. 
Flats, 1, 28-29, 31, .50. 
Flax, native, 33. 
Flintios, 64, 141. 
Floaters, 55. 
Flood-plains, 49. 
Fluviatile deposits, 49-50. 
Fluvio-marine deposits, 49, 50. 
Forest, 1, 2. 
" Formations," 77. 

Fourth Branch of Tairua River, 83, 86, 88. 
Fragmental rocks (.see Agglomerates, Breccias, and 

Tuffs), 3, 27, 43, 46, 47. 
Eraser, C., 4, 6, 67. 
Eraser, S. E., 145. 
Frictitm breccias, 124. 
Fyfo, A., 6, 162. 
Fuller's earth, 57. 



G. 



Galena, 56. 59, 61, 114, 115. 134, 146. 

Galvin, P., 4, 6. 

Gases, undergn)un<l, 67. 

Gates and Hecloii rock-breakers, 144. 

Gauvain, VV. P., 6, 145. 

Gentle Shepherd Claim, Neavesville, 84. 

George lode, Wailii, 129, 163, 164, 166, 167, 170. 

Geothermal gratlient, 18, 66, 67. 

Gilmour, J. L., 6, 145. 

Gisborne, 33. 

Glamorgan Claim, Whangamata, 61, 95, 96-97. 

Glamorgan Gold-mining Company (Limited), Auck- 
land, 96. 

Glamorgan reefs, Whangamata, 97. 

Glass, volcanic, 48. 

Gold, methods of occurrence of, 58, 136. 

Gold, proportion of, to silver, 58, 62, 101, 136, 137, 
139. 

Gold, selenide of, 137. 

Gold, telluride of (nee Tellurides), 58. 

Gold, yield (see Output). 

Golden Arrow Claim, Neavesville, 84. 

Qolden Belt Claim, Neavesville, 58, 61, 63, 84-86, 
174, 177. 

Golden Belt Gold-mining Company (Limited), 
Auckland, 15, 84-86. 

Golden Belt Mine, Neavesville, 39. 



Golden Cross, 56, 59. 60, 65. 101, 105, 122, 133, 

174, 176, 179. 
Golden Cross Claim, Waitekauri, 9, 13, 17, 39, 53, 

104, 108-111, 173. 
Golden Cross Company, Auckland (.see Waitekauri 

tiold-mining Company), 109. 
(iolden Cross Mine, Waitekauri. 26, 104, 109. 
Golden Cross reef, 104, 110, 111. 
(iolden Cross vein-.system, 44. 
(Jolden Hills Company, 76. 
{it)lden Hills Mine, Lower Tairua, 77. 
Goklon Reefs Claim, Gumtown, 72, 74. 
! (iold Hill, Utah, U.S.A., 3, 179. 

(iold-mining companies, 25. 
I Goldwater Claim, Whangamata, 96, 97. 
(ioldwator C<>mi)any, 96. 
Goldwater reef, Whangamata, 96, 97. 
Goldwin Claim, Wharekawa, 93-95. 
Gordon, H. A., 4. 
Gonl(>n Claim. Maratoto. 103. 
Gordon E.xti-iided Claim. Maratoto, 103. 
Gorges, 8, 28. 29. 
Gorrio's workings, Tairua, 83. 
tio.s.san, (>2, 77, 122. 
Oriibeu, 5, 51. 

Grace Darling Claim, Wailckami. 108, 111-112. 
Grace Darling reof, Waitekauri, 112. 
Grace Darling Stream. Waitekauri, 111. 
Grace kxle, Waihi. 129, Iti.!. 164. 1()5. 170. 
(ira)iam, K. M.. 4. 

Grand Junction Mine (.see Waihi Grand Junction). 
Grauwackc, 38, 49, 124. 
(Jroiit .Mexican Claim, Ohui, 89, 91, 92. 
(Jreen carbonate of copper, 59. 
(irecn vitriol, 59. 
Cirinding, tine, of ores, 23, 24. 
Grit-bed.s, 47. 

Groundiiuis,s of volcanic rocks, 41, 44, 45, 46, 48. 
Ground- water level, t)2, 67, ()8, 171. 
Orihtistein, 54, 55. 
CJumtown, 16, 52, 61, 72-75, 173, 175. 



H. 



Hadlicld crushers. 21. 162. 

Ha(MisIcr, H., 5. 

Hand-])icking of ores, 107. 

" Hard bars," 55. 

Harp-of-Tara Claim, Ohui, 89. 

Harris, G. E., 4. 

Hartridges leader, Komata, 106, 107, 108. 

Haulage, underground, 19, 21. 

Hauraki Division, 3, 16, 35. 

Hauraki (lulf, I. 

Hauraki Peninsula, 30, 38. 

Hauraki Peninsula Exploration Company (Li- 
mited), Ijondon, 15, 25, 95. 

Headlands, 31. 

Hector, Sir J., 4, 5, 8, 9, 21. 

Herald Claim, Whangamata, 96, 97. 

Hessite, 13, 58, 101, 103, 104, 1.59. 

High-grade ore, 7, 8, 74, 78, 83, 90, 99, 107, 134, 
141, 1.59, 166. 

Hihi Creek, 29, 173, 17.5. 

Hikurangi, 32. 

Hikutaia, 3, 100, 108. 

Hikutaia Gold Syndicate, London, i;{, 15, 101, 102, 
176. 

Hikutaia River, 2, 28, 29, 32, 39, 44, .50, 100, 108. 

Hikuwai, 31. 

History of mining-development. 7-17. 

Hoisting or winding, 19, 144, 158, 162, 171. 

HollLs, W., 8, 10. 

Hollis's Blow, Waitekauri, 117. 

Homunga, 2. 



186 



Hoinuiiga Bay. 4i), .V.). 121. 

Homiinga River, 32. 

Hone Werahiko, 10. 

Htirahora, \\'aikati) River. 145. 

Horn adit level, W'aitekauri Claim, 113, 114, 11.5. 

Hornblende, 41, 44, 47, 48, 49, 109. 

ll<irnblende ande.site, 40, 44, 126. 

Hornblende dacite, 76. 

Horublende-hyperstheue audesite, 41, 45, 49, 94. 

Hornblende-pyroxene andesite, 171. 

Hornblende-pyroxene dacite, 42. 

Hornibrooke, H. P., 75. 

Hornstone, 48. 

Hot springs, 93. 

Hot Water Beach, 44. 

Huanui Claim, Waitekauri, 108, 1 13. 

Huanui Creek, Waitekauri, 113. 

Huia Creek, Hikutaia River, 32. 

Hutton, F. W., 4. 

Hydro-electric power plants, 145. 

HyalopiUtic structure, 41, 44, 45, 46, 49. 

Hydrated silica, 56, 60. 

Hydrothermal action and alteration, 3, 37, 47, 52, 

54, 89, 94, 118, 124, 12.5, 158, 173, 175. 
Hydrothermal solutions, 53, 85, 132. 
Hypersthene, 41, 48. 
Hypersthene-andesite, 37, 44, 45, 49. 
Hj'persthene-hornblende andesite, 41. 



Igneous rocks, 3, 27, 39-51. 

Illumination of mines, 18. 

llmenite, 41. 

Impoverishment of ores in depth, 10, 61, 65, 66, 81. 

Inca Creek, Wharekawa, 92. 

Incognito Creek, ilaratoto, 104. 

Indicators and indicator-veins, 58, 64, 103, 137, 

141. 
Influence of rock-walls on veins, 63-64. 
IngersoU-Rand air-compressor, 171. 
Inglewood Claim, Owharoa, 118. 
Inoceramui kaasti, 38. 
Intrusive rocks {see Productive dacite, Waihi), 36, 

37, 49, 63, 105, 121, 124, 125, 126, 128. 
Iodine in mineral waters, 33. 
Irving Claim, Maratoto, 103. 
Islands, 3, 30, 31. 



Jarman, A., 6. 

Jasper, 56. 

Johnston, W. H., 6, 145. 

Joint-planes, 47. 

Jubilee adit, Waitekauri, 115. 

Jubilee Claim, Waitekauri, 9, 25, 61, 108, 113, 114, 

115, 177. 
Jubilee Hill Claim. Waitekauri, 113, 114, 115, 116, 

177. 
Jubilee Syndicate, London, 115. 
Jubilee- Waitekauri reef, 52, 115. 
JuUa reef, Maratoto, 14, 102. 
Jurassic rocks, 3, 27, 35, 38, 124. 
Just-in-Time Claim, Komata, 13. 



K. 



Kaitarakihi, Mount, 1. 

Kaolin, kaolinite, and kaolinitic material, 56, 57, 
58, 61, 62, 77, 79, 82, 83, 97, 119, 120, 137, 167. 
Kapowai, 52. 
Kapowai Claim, Gumtown, 72-74. 



Kapowai Gold-mining ('oni|)any (Limited), Auck 

land, 16, 72. 
Kapowai River, 16, 47, 72. 
Karangahake, 8, 123, 124, 180. 
Karangahake Gorge, 8, 32, 51, 119, 123. 
Karangahake Mountain, 118. 
Kathleen Creek, Waitekauri, 112. 
Katikati, 124. 
Kauaeranga, 173, 175. 
Kauaeranga River, 1, 26, 32, 47, 119. 
Kauri, 2, 18, 98. 
Kauri-gum, 2. 
Kawhia, 33. 

Kiln adit, Golden Cross .Mine, 109. 
Kindly country, 63, 140. 
Kirikiri, 14, 173. 
Kirikiri River, 174. 
KloncUke Claim, Omahu, 99-100. 
Klondike Creek, Omahu, 100. 
Komata, 12, 13, 52, 53, 56, 59, 60. 64, 65. 101, 

105-108, 122, 133, 173, 174, 175, 176, 179. 
Komata Amalgamated Claim, 13. 
Komata Claim, 9. 

Komata Gold-mining Company, 12, 13, 17, 23, 105. 
Komata Queen Claim, 13, 
Komata Reefs Claim, 105, 106, 107, 177. 
Komata Reefs Gold-mining Company (Limited). 

London, 9, 13, 25, 26, 105. 
Komata Reefs mill, 23-24, 106. 
Komata Reefs Mine, 105-108. 
Komata River and Valley, 1. 3, 13, 39, 50, 105, 

106, 112. 
Ki'upp mills, 92. 
Kuaotunu, 38, 51, 89. 



Labradorite, 41. 

Last Chance Claim, Uhui, 89. 

Last Shot SyniUcate, 99. 

Lauraontite, 57. 

Lava, 3, 27, 28, 31, 36, 37. 40, 43, 44, 45, 46, 47, 64. 

Lavington's reef, Komata, 106, 107, 108. 

Lead, 180. 

Leahy, D., 8, 10. 

Leases, mining, 24. 

Lee, R., 10, 143. 

Leucoxene, 41, 47, 54. 

Levels, distance between, 19. 

Lighting of mines, 19. 

Lignite, 36. 

Lime in calcite, source of, 53. 

Limonite, 56. 

Lindgren, W., 6, 51, 179. 

Liverpool reef, Maratoto, 101. 

Low-grade ore, 7, 14, 74, 76, 82, 87. 101, 107, 108, 

111, 134, 141, 176. 
Lower Tairua {see Tairua, Lower). 
Lowrie Bros., 108, 109. 
Luck-at Last, 52, 53, 175. 

Luck-at-Last Claim, Wharekawa, 15, 16, 61, 92, 93. 
Luck-at-Last Gold-mining Company (Limited), 

Auckland, 16, 92. 
Lumbering, 2, 98. 



M. 



Mackaytown, 7, 18, 59, 62, 119-121, 180, 181. 

Maclaren, J. M., 6. 

Madden's Follv Claim, Owharoa, 117. 

Magazine lode," Waihi, 129, 146, 150. 

Magmatic sloping, 41. 

Magnetite, 41, 47, 54, 56. 

Majurey, R., 10. 

Malachite, 59, 139. 



187 



Manaia Hill Series, 38. 

Manami t'laiiii, Whangainata, 15, 95. 

Mananu Gold- mining Company, 25, 95. 

Mangahara Creek, 108, lib, 118. 

Manganese, oxides of, 56, (iO, 02, 87, 97, 102, 103. 

107, 110, 111, 112, 122, 139, 148, 159. 
Manganiferous eakite. 50, 59, 02, 101, 107, 111, 

112, 113, 132, 133, 134, 138, 140, 150. 
Mangrove swamps, 28, 30, 31, 33. 
Manuka, 32. 
Maori, 2, 7, 12, 34. 
Maori Dream Claim, Ohui, 91. 
Maori Dream Gold-mining Company (Limited), 

London, 89, 91. 
Maori Dream reef, Ohui, 91. 
Maoriland Claim, Waitekauri, 9, 01, 108, 110-117. 

177. 
Maoriland Gokl-mining Company (Limited), Waihi, 

116. 
Maoriland vein-formation, 110, 117. 
Maorilander Claim, Ohui, 89. 

Maratoto, 13, 14, 39, 52, 53, 50, 58. 59, 00, 03, 04, 
65, 100-105, 108, 113, 133, 169, 173, 174, 176, 
179. 
Maratoto Claim, McBrinn's Creek, 13, 14, 58. 
Maratoto Gold-mining Company, 13. 
Maratoto Gold-mining Company (Limited), Auck- 
land, 13. 
Maratoto reef, 52, 101, 102, 103, 177. 
Maratoto River and Valley, 2, 3, 14, 30, 100, 10 1, 

102, 104. 
Maratoto United Claim, 13, 14. 
Marcasito, 59, 61, 122. 
Marriman, 10. 
Marshall, P., 0. 
Martha-Edward lode, Waihi, 52, 132, 140, 177, 

178. 
Martha E.xtended Gold-mining C<>ni|)any, Auckland, 

10, 143. 
Martha Hill, Waihi, 10, II, .{9, 123, 124, 125, 120, 
127, 128, 1.30, 132, 140, 141, 142, 14.5. IM. 174, 
178. 
Martha lode, Waihi, 10. II. 12, 53, 02, 100, 127- 
130, 132, 133. 137, 1.39, 141-l.-)0, l.52-l.-)4. 101. 
163, 1»U, 16.5, 168-171, 177, 179. 
.Martha .Mine (.sec Waihi Mine and .Martha .section 

of Waihi .Mine). 
.Martha north loader, Waihi, 14(i. 
Martha section, Waihi .Mine. 16, 58, 14.V157, 161. 
Martha-Welcomc-Edward lode, Waihi, 128. 130 

150, 155. 
Mary lode, Waihi, 67, 142. \M. 170. 
Mascotte l.ule. Waihi, 129. 100, 172. 
McBrinn, K., 13, 100. 
McBrinn's (reek, .Maratoto, 13, 100, 101. 
McComIno, J., 5, 7, 8, 10, 77, 143. 
McGregor, J., 88. 
McKay, A., 4, 5, 40, 117. 
McLiver Bros., 84. 
McWilliains, — , 90. 
Mean annual temperature, 2. 
Me and Rowe Claim, Owharoa. 117. 
Meanders, 32. 

Means of communication, 3. 
Melanterite, ~>'J. 

.Mercury and mercury ore (<ice Cinnabar), 18, 180. 
.Mercury Bay, 72. 

.Metasomatic replacement, 54-.56, 57, 82, 134. 
MeUllization, 3, 43, 46, .52, 54, 92, 100, 121 132 

134, 173. 
Metallo-genetic epochs, ,54, 132. 
Metallurgy (see Milling-practice). 
Metrosiderov robuMtt, 2. 
MelTosideros tomerUosa, 2. 

.Micropoccilitic structure of groundmas.s, 41, 44, 45. 
-Milling practice, 21-24. 



.Miue-drainage, 11, 12. 

Mine-gas, 18, 67. 

Mine-timber, 2, 18. 

Mine-waters, 09-70. 

Mineral deposits, types of, 60, (il, 134-140. 

Mineral production (see Output of gold and silver), 

17-18, 173. 
Mineral veins, 52-70. 
Mineralization, 52-50. 
Mineralization, periods of, 52. 
Mineralogy, 56-00. 
Mining boom, 16, 17, 24, 88. 
Mining-costs, 26. 

Mining methods and practice, 18-21. 
Miocene, 37, 44. 
Mispickel, 59. 
MoanataiaM fault, 51, 167. 
Monarch Claim, 'I'airua Broken Hills, 82. 
Montgomery, A., 58, I.VJ. 
Moore vacuum -HIters, 21, 23, 100. 
.Morgan, P. G., 5, 0, 40, 42, -t8, 57, 139, 141. 
.Morgan, R. J., 106, 181. 
-Muclstones, 36, 40, 47. 
Muriated saline water, 33. 
.Murray, R. A. F., 6. 
.Mushroom type of sinter, 01, 89. 
Mustard gold, 143. 



N. 

Native land, 7, 24. 

Neave's Bay, 75. 

Xeavesvilie) 3, 14, 15, 39, 52, 61, 62, 83-88, 98, 
173, 175, 176. 

Necks, volcanic, 28. 

Nell Claim, Ohui, 88, 89. 

New Golden Cro.ss Gold-mining Company, Auck- 
land, 109, 111. 

New .Maratoto Company (Limited), 14. 

New Waitekauri Gold-mining Company (Limited), 
Auckland, 113. 

New \'iia.r reef. Tairua Broken Hills. 78, 81. 

New Zealand Broken Hills (iold-mining Company 
(Limited), London, 77. 

New Zealand Cinnabar Company (Limited), 119. 

New Zealand Jubilee Gold-mine (Limited), London, 
11.5. 

Ngapuketurua, 32. 

Nicholl, W., 10. 

Nickel, 110, 139. 

Night reef, Tairua Broken Hills, 78, 79, 80. 

Nikau palm, 2. 

Nominal capital of mining companies, 25. 

Norah shaft furnace, 119. 

North Royal lode, Waihi, 146, 152, 153. 



o. 



OKserver Claim, Whangamata, 96. 

O'Connor, M., 72. 

Officers connected with the work, 4. 

Ohinemuri mining district, 7, 8, 9. 

Ohinemuri County Council, 24, 25. 

Ohinemuri River and Valley, 1, 2, 3, 28 29 32 

39, .30, 51, 68, 118, 119, 123, 127, 143. 
Ohinemuri River Syndicate, 143. 
Ohinemuri Syndicate, 118. 
Ohinemuri Survey District, 1, 44, 46. 
Ohui, 3, 15, 31, 52, 60, 62, 63, 68, 88-92, 173, 174, 

17.5, 176. 
Ohui Creek 88. 

Ohui-Wharokawa l)each, 50, 88. 
Oligoclase, 42, 48. 
Oligoclase-andesine, 41. 



188 



Old Maratoto Claim, 58. 

Omahu, 3, 14, 46, 173, 175. 

Omahti Mines (Limited), 99. 

Omahu Peak, 100. 

Omahu River, 1, 28, 39, 49, 98-100. 

O'Neill, S., 10. 

Opal, 56. 

Opencuts, open-cutting, 34, 72, 116. 

Ore, analyses of, 22, 58, 135, 136, 139, 140, 159. 

Ore, argentiferous, 13, 14, 52, 96, 101, 102, 103. 

Ore, composition of, 21. 

Ore-depcsits, 62-66. 

Ore-reserves, 108, 160,n61, 168, 178. 

Ore-shoots {nee Shoots of ore). 

Ore to ore (.sec Back-to-back), 64. 

Ore, treatment of {.see Milling-practice). 

Oro Fino Mine, De Lamar, Idaho, U.S.A., 179. 

Orokawa Bay, 29, 30, 51. 

Orokawa Beach, 29, 50, 51. 

Orokawa Creek, andesites of, &c., 121. 

Orthoclase {see iSanidine), 41. 42. 

Orthoclase, secondary (see Valencianite). 

Orua Hot Spring, 33. 

Otahu Inlet, 29, 31, 97. 

Otahu River, 1. 

Oteao Stream, Gumtown, 72. 

Outcrop, ore richer in, 16. 

Output of gold and silver, 9-16, 17. 72 ei seq.. 123, 

143, 146, 147, 162, 168, 169, 172, 173. 
Oxley's Gully, Tairua Harbour, 49. 
Oxidation of vein-material, 62. 
Oxidized belt in Waihi Mine, 62, 139, 148, 149, 150. 



P. 

Pachuca, Mexico, 3. 

Pacific Ocean, 1, 3. 

Paeroa, 3, 32, 46, 123, 181. 

Paeroa Junction, 123. 

Paiakarahi Creek, 100, 101. 

Pakirarahi Mountain, 63, 83, 84, 85, 86, 175. 

Paku Island, 31. 

Pan-amalgamation, 13, 101. 

Park, J., 5, 6, 51. 

Parson's steam-turbines, 22, 162. 

Passes or shoots, 19. 

Pay Rock reef, Maratoto, 101. 

Peaks, 28, 29, 30. 

Peel's Creek, Maratoto, 13, 39, 100, 101, 104. 

Pennel's house, Waihi Beach, 121. 

Perham, T., 5. 

Periods of mineralization, 52. 

Periods of volcanic activity (-see First Period, 
Second Period, Third Period), 3, 36, 37. 

Perseverance Claim, Gumtown, 72. 

Persistence of ores in depth, 64-66, 142, 178. 

Petrology, 40^2, 44, 45, 46, 47. 

Petzite, 58. 

Phoenix Claim, Ohui, 63, 67, 68, 89-91, 176. 

Phoenix Gold-mining Company (Limited), Auck- 
land, 89. 

Phoenix-Dreadnought Claim, Ohui, 89. 

Phoenix Hill, Ohui, 90. 

Phoenix-Pukewhau Claim, Wharekawa, 16, 92, 93, 
94. 

Phormmm tenax, 33. 

Physiography, 27-34. 

Pilotaxitic structure, 41. 

Pinches, 64. 

Pipi Creek, 76. 

Pipes of ore, 14, 46, 52, 61, 63, 73, 76, 77, 78, 84, 
160, 177. 

Pitchstone, 47, 48. 

Plagioclase, 40, 41, 47. 

Plains (see Flats), 123, 127. 



Plateaux, 28, 29, 49. 

Pleistocene, 38, 49-50. 

Pliocene (see Third Period of volcanic activity), 

28, 36, 37, 46, 49, 51, 174. 
Plugs, volcanic, 30, 47, 100. 
Pohutukawa, 2. 
Pond, J. A., 4, 159. 
Population of subdivision, 2, 3. 
Porphyrite, 38. 

Portsee Claim, Waitekauri, 112. 
Pre- Jurassic rocks, 3, 27. 35, 38, 124. 
Pride of Waihi Claim, 68, 169, 171. 
Pride of Waihi Gold-mining Company, Auckland, 

171. 
Prince Charlie Gold-mining Company, 96. 
Prmcoss Claim, Waitekauri, 112. 
Princess lode, Waihi, 129, 146. 
Prioress Claim, Waitekauri, 112. 
Privateer Claim, Maratoto, 103. 
Proclamation of Ohinemuri Goldfield, 7, 8. 
Produce-gas plants, 145. 
Production {see Mineral production. Output of gold 

and silver). 
" Productive " dacite, Waihi, 125, 127, 134, 140, 

149, 151, 152, 163, 164, 169, 170, 178. 
Progress Claim, Waitekauri, 112. 
Proportion of gold to silver in ores and })ullioii, 

58, 62, 101, 136, 137. 
Propylite, 40, 54, 58, 63, 64, 70. 163, 169. 
Propjlitic alteration, propvlitization, 39, 40, 42, 

43, 45, 54-55, 124, 125, 140, 148. 
Prospecting, cost of, 26. 
Prospectors, 24. 
Proustite, 59, 142. 
Pseudomorphs (see Quartz replacing calcite), 41, 42, 

48, 56. 
Pug and puggy selvages, 64, 88. 114, 116, 126, 127. 

133, 135, 170. 
Puketui, 48, 77. 

Pumice and pumiceous rocks, 46, 47, 50, 76, 171. 
Pumping, pumps, &c., 18, 65, 68, 69, 143-144. 
Punon reef, Tairua Broken Hills, 78. 
Puru-i, 3, 14, 174. 
Puriri mineral water, 33. 
Puriri River, 1, 14, 28, 29, 39, 83, 86, 98, 99. 
Pyramid Claim, Waitekauri, 112. 
Pyrargp-ite, 59, 142. 
PjTite,'40, 54, 56, 59, 61, 62, 63. 67, 134, 135, 136. 

'138, 142, 159. 
Pyrite, argentiferous, 136. 
Pyi-ite Creek, Taunia River, 88. 
PjTitization, 63, 76, 116, 121. 
PvToclastics {see Agglomerate, Breccia, and Tuff), 

"46. 
Pyrolusite, 60. 
PvToxene, 47, 48, 126. 
Pyroxene-andesite, 40, 41, 44, 45, 49, 72, 89, 91, 

"121, 125, 158. 
Pyroxene-dacite, 93, 109, 124. 
PjToxene-rhyolite, 42. 



Q. 

Quartz Creek, Tairua River, 28. 

Quartz in veins, 56, 60, 61, 65-66, 132-140. 

Quartz, primary, in volcanic rocks, 41, 47, 48, 49. 

Quartz, pseudomorphous after calcite, 56, 60, 65-66, 
90, 96, 101-106, 110-114, 122, 133, 134, 138, 139, 
148, 150, 153, 158, 159, 164, 165, 176, 179. 

Quartz, secondary, in rocks (see SiUcification, &c.), 
54, 56. 

Quartz-sericite rocks, 47. 

Quartz veins (see Veins, mineral.) 

Quartz, vein-, character of, 56, 60, 68, 72 ei seq. 



189 



R. 



S. 



Radical Olaim. Owharoa, 118. • 

Radical reef, Owharoa, 118. 

Rahu Creek, Mackaj-town, 120. 

Railways. 3, 12, 12.3. 

Rainfall, 2. 33, 68. 

Rai.sed beaches, 30, 51. 

Raniarama beach, oO. 

Ramarama Creek, 42, 4.5, 98. 

Rangihaii River, 16, 46, 72, 74. 

Rata, 2. 

Ra\ipo, 32. 

Ravenswood Claim, Maratoto, 102. 

Ready Bullion Claim. Xeavesville. 84, 86, 87. 98. 

Realm Reef, Waitekauri, 110. 

Recent deposits, 38. 49. 

Redjang Lebong district, Sumatra, 3, 79, 180. 

Retinini; of gold, 140, 181. 

Regina lode, Waihi, 129, 141, 146, 1;J0, ir>4. 

Rejuvenation of ore-bearing solutions. I34#14l. 

Replacement deposits and ore. '>2, a."), 82, 13r>. 
Replacement of calcite by (luartz {jicp Quartz 

pseudomorphous after calcite). 
Reptile i)ass, Waihi Mine, l')*). 
Retreat Claim, Maratoto, 102. 
Reversal of drainage, 32, ol. 127. 
Rex lode, Waihi, 129, 146, 152, 153, 158. 
Rhodocrosite (see Manganiferous calcite), 59. 
Rhopalo-itylis mipidtt. 2. 

Rhyolite and rhyolitic rocks (iiep Biotite rhyolitO, 
Dacite-rhyolite, P\Toxene - rhyolite. Silicified 
rhyolite, Spherulitic rhyolite, Tridymite-rhyo- 
lite), 3, 21» 28. 29. 30, 31, .52, 33, 36, 37, 41, 
43, 46-48, 49, .52, 54, 56, 57, 58, 60, 61, 63. 64. 
66, 67, 124, 125. 
Rhyolitic breccias, 27, 36, 37, 46, 47. 
Rhyolitic tuffs, 36, 37, 46, 47. 
Ribbon-structure in veins, 90. 
Rich ore (tee High-grado ore). 
Rickard, T. A., 24. 
Ridges, 28, 29, 30. 
Rill, on the. 20. 

Rising Sun Claim. Owharoa, 9, 61. 117. 118-119. 
Rising Sun Kxteiided Claim. Owharoa, 118. 
Rising Sun Oold-mining Company (Limited), Auck- 
land, 118, 177. 
River capture. 32. 
River-terraco.s, 29. .">(). 
Roads, 3, 72. 89, 100. 105. 108. 114. 
Rock-alteration. :!", .")3. .54-56. 
Rock-benches. 30, 31, .">(). 
Romulus Claims. 25. 
Roscoe. H. E., 65. 
Rosenbu.sch, H., 54. 
Rosemont Claim, Waihi. 10. 
Rosemont Hill, Waihi, 123, 124, 126, 128. 
Rosemont Gold-mining Company, 143. 
Rosemont Mine, 158. 
Rotorua, 53. 

Roval lode, Waihi, 53, 55, 66, 127, 129, 130, 1.32, 

13.5, 140, 141, 142, 146, 150, 151-1.52, 1.56. 157, 

158, 161, 163, 164, 166, 167, 170, 171, 177. 178, 

179. 

Royal Standard Gold-mining Companv, London, 

25, 97. 
Ruahine-Alpine line of folding, 53. 
Ruanui reef, Whangamata, 9.5, 96. 
Ruby silver, 59, 142. 
Russell, T. H., 9, 108. 
Rush, 7, 8, 14, 16. 
Rutley, F., 5. 



Sands, sand-dunes, 27, 29, 31, 50. 

Sanidine, 47. 

Scenery, 3. 

Schiflf,"F., .5. 

Schlnrleinmer, C, 65. 

Scotia Claim, Waitekauri, 9, 108. 114, 177. 

Scotia Gold- mining Companv (Limited), Auckland, 

114. 
Second Period of volcanic activitv. 3, 27, 30, 36, 37, 

43-t6, 49, .52, .54. 124. 125, 173. 174-175. 
Secondarv enrichment, 62. 65. 73, 96, 99, 117, 141, 

142, 143. 
Sedimentary rocks, 3, 34, 35, 38. 40. 53. 
Selenide. .59. 137. 
Selenium, .59, 137, 1.58, 181. 

Sequence of mineral deposition in veins, 132-134. 
Sericite, ">4, .56, 57, 134. 
Shafts, 18. 

Shaw (prospector), 122. 
Sheet Anchor Claim, (Jmahu. 98, 99. 
Sheet Anchor (iold-niiniug Companv. 99. 
Sheeted zones. 52. 85, 87. 90. 102. 111. 130, 177. 
Shoots of ore, 62, 63. 64, (i5. 6(i. 140-143, 173-174. 

175, 176, 178. 179. 
Shore-line. 30-31. 
Shrinkage sloping. 20. 148. 
Siderite, 41, iU. 

Siever's leader, Tairua Broken Hills. 79. 
Signalling in shafts. 19. 
Silica (see (Juartz). 58, 61, 6.5. 137. 
Siliceotis sinter (see Sinter). 
Silicification, .5.5, 56. fM). 61. 66, 72 H aeq., 110-111, 

112. 116, 117, 121, 132, 134, 158, 175, 178, &c. 
Silicitied dacite breccia. 61. 116. 117. 
Siliciticd proi)ylite. 55. 103, 106, 120, 158, &c. 
Silicified rhyolite and rhyolite tuff, 56. 72, 74, 76, 

77, 81, 84, 90, 97, 98, i21. 176. 178. 
Silicified tuffs. 16, 27, 72, 73, 74, 76, 84, 85, 86, 98, 

116, 176. 
Silicified wood, 56. 
Silver, 58. 62. 76, 136. 
Silver glance, .59. 

Silver King Claim. Whangamata, 96. 97. 
Silver (^ueen Claim. .Maratotfi. 102. 
Silver Queen reof, .Maratoto. 102, 103. 
Silver, proportion to gold, 58, 62, 101, 1.36. 137. 
Silver, selenide of, 137. 

Silver, telluride of (he.ssite), 13, 58, 101, 103, 104. 
Silverstream Claim, Maratoto, 100, 102-103, 104, 176. 
Silverstream Gold and Silver Mining Company, 14. 
Silverstream Gold-mining Company, Auckland. 1 12. 
Silverstream reef, Maratoto, 14, 58. 
Silverton Claim. Waihi. II, 171. 
Silverton (Jold-mining Companv, Auckland, 10, 14.3. 
Silverton Hill. Waihi. fl2. 123. 1 24, 126, 128, 158. 
Silverton lode, Waihi, II, 129. 132, 1.58, 160, 171. 
Sinter, silicef)us, 37, .52, .53, .59, 61-62, 63, 175, 178, 

180. 
Skerries, 30, 31. 
Skey, W., 4, 1.59. 
Skips, 19. 

Slickensides, 79, 8.5, 96, 127, 1.32, 16.3, 170, 171. 
Slidy hea<ls (see. Slickensides). 
Sliming of ores, 24, 144. 
Slipper Island, 31. 
Sluicing. 76. 

Smile-of Fortune Claim, Owharoa, 61, 117, 1 18, 177. 
Smile-of-Fortune reef, Owharoa, 118. 
Smith, S. P., 4. 
Solfatari.sm, .54. 
Sollas, W. J., 5, 40, 42. 
Source of lime in calcite veins, 53-.54. 
Southern Cross reef, Waitekauri, 100. 
Specimen -stone, 7, 14. 



190 



Spheroidal alteration and weathering, 40, r)5. 
SphtMulitio rhvolito, 70, 81, 90, 91, 117, 121, 122, 

125, 127. 
Sphcnditir structure, 41, 47, oG, 78, 118. 
" Spill ■■ of vein-forininj; solutions, 02, 140. I.i8. 
Spitzkast«!n, 21, 102. 
Spitzlutte, 21. 

Spratt pass, Waihi Mine, 157. 
Springs, 33. 

Springs, hot, 53, 00, 120. 
Square sets, use of, 19. 
Stacks, 30, 31. 
Stamps, battery, 21, 22, 23. 

Statistics, mineral. 7, 9. 12, 13, 14, 15, 17, 143 et seq. 
St. Hippo Claim, Maratoto-Waitekauri Saddle, 13, 

14. 100. 
Stilhite, 57. 

Stock-work deposits, 60, 118, 177. 
Stony Creek, 49, 76. 
Stoping, 19, 20. 
Stoping, magmatic, 41. 
Stoping- widths, 19. 
Stoping, shrinkage, 20, 148. 
Structural features of mineral veins, 63, 04. 
Structure of rocks (see Hyalopilitic structure, Micro- 

poecilitic structure, Pilotaxitic structure, Sphe- 

rulitic structure). 
Structure of vein -material, 60-61. 
Sulphides (.see separate species). 
Sulphide enrichment, 141, 142. 
Sulphide ore, Waihi Goldfield, 134-138. 139. 140, 

141, 142. 
Surprise lode, Waihi, 129, 145. 
Sutcliffe Creek, Wharekawa. 93. 
Swamps (see Mangrove swamps). 32. 33, 50. 92. 



Table Mountain. 30. 36. 46. 49. 72. 

Table of formations, 37-38. 

Table of mineral production, 17, 173. 

Table of output of various lodes in the Waihi Mine. 
146-147. 

Table showing the lengths and widths of the veins 
and ore-shoots. Waihi Mine, 153-157. 

Taihoa Gold-mining Company, 15. 87. 

Taipari Claim, Waihi Beach," 121. 122. 

Tairua, 3, 14-15, 26, 44, 48, 56, 58. 61. 173. 

Tairua. Lower, 63, 76-83, 175, 176. 

Tairua Broken Hills, 28. 52. 53, 61. 62, 67. 

Tairua Broken Hills Claim, 14. 77-81, 83, 175, 176. 

Tairua Broken Hills Gold-mining Companv (Li- 
raited), 14-15, 17, 25, 77. 

Tairua Broken Hills Mine, 64, 77. 

Tairua Dawn Claim, Tairua, 77, 81, 83. 

Tairua Dreadnought (Limited), Auckland. 91. 

Tairua Extended Claim, Tairua, 77, 81, 83. 

Tairua Gem Claim, Tairua, 77. 

Tairua Gem Companv, 83. 

Tairua Golden Hills Claim, 77, 81-82, 176. 

Tairua Golden Hills Mining Company (Limited), 
Auckland, 15, 81. 

Tairua Harbour, 31, 49, 75. 

Tairua Junction fUaim, 77. 

Tairua Leads Claim, 81, 83. 

Tairua Monarch Consolidated Claim, 77, 82-83, 176. 

Tairua Monarch Consolidated Gold-mining Com- 
pany (Limited), Auckland, 15. 82. 

Tairua Mines (Limited), 77. 

Tairua Reefs Claim, 77. 



Tairua River anrl Vallev, 1, 2, 3, 14, 28, 29, .30. 31. 

32, 44, 47, 49, 52, 76,' 77, 81, 83, 88. 
Tairua Surrey District, 1, 46, 92. 
Taiwawe River, 33. 
Takerci Crock. Paeroa, 181. 
Talisman Mine, Karan^ahake, 124, 180. 
Talus, 49, .50. 

Tangatara Creek, Wharekawa, .59. 
Tapu, veins in pre-Jurassic rocks at, 38. 
Tararaire, 2. 
Tarariki Creek, 181. 
Tawa, 2. 

Te-ao-marama, 9, 13. 

Te-ao-marama Claim, Komata, 9, 13, 10.5-108. 
Te-ao-marama Licensed Holding, 12. 
Te-ao-marama tunnel, 113. 
Te Aroha, 10, 51. 
Te Aroha, Mount, 53. 
Te Karo beach, 75, 76. 
Tellurides of gold and silver. 13, 58, 101, 103, 104, 

143. 
Telluride Proprietary Claims, 100, 103-104. 
Telluridfe Proprietary (Limited). Auckland. 14. 103. 
Te Moanuanu Stream, Whangamata, 95, 174. 
Temperature of springs, 33. 
Temperature-gradient, 18, 06. 
Temperature, mean annual, 2. 
Temperature, underground, 66-67. 
Te Puru Stream, Waihi Beach, 121. 
Terraces, 29, 34. 50. 
Tertiarv earth-movements, 28, 50. 
Tertiarv vulcanism, 27, 36, 37. 39-49, .52, 124, 173. 
Thames, Thames Goldfield, 7. 18, 26, 64, 65, 67, 70, 
* 141, 167. 

Thames County Council, 25. 
Thames-Hauraki Plain. 45. .50. 
Thames River and Vallev. 1 , 3, 28. 29. 30. 32, 33. 

49, 51, 123. 
Thames Subdivision, 1. 36. 38, 39. 40. 45, 53, 98. 

174. 
The Bluffs, Neavesville, 85-86. 170. 
The Caves, Lower Tairua, 77, 78. 
The Wires. 29. 32. 88. 
Third Period of volcanic activitv, 27, 28, 29, 36. 

37, 43, 44, 46^8. 49, 52. 54. 124. 125, 173, 174. 

175, 178. 
Tiki, Coromandel. 38. 
Timbering, mine, 2, 18. 19, 20. 
Tilsley Bros., 12, 98. 
Ti-tree Creek, Lower Tairua. 49. 76. 
Tokatea Hill Series, 38. 
Tokatea reef. Coromandel. 126-127. 
Tonopah, U.S.A., 3. 
Topographical work. 4. 
Topography, 27-34. 
Torehine Series, 53. 
Tracks, 3, 72. 83, 87, 100, 10.5. 
Tramways (see Aerial trams), 97, 106, 108, 116. 
Transylvania, Europe, 3. 
Transverse belts influencing ore. 64. 
Treasure Island reef. Waihi Beach, 122. 
Treatment of ores (see Milling-practice). 
Tree-fern, 2. 
Tremain mill, 99. 
Triassic period, 38. 

Tributers, tribute-system, 8, 10, 24, 74. 
Tridymite, 47, 48. ' 
Tridymite-rhyolite, 47, 48, 181. 
Triumph Claim. Lower Tairua, 82, 83. 
Trout borehole, Waihi Mine, 67, 127. 
Trout level, Waihi Mine, 127. 

Tube mills, tube-mill products, 21, 81, 106, 144, 162. 
Tuffs (.see Andesitic, Dacitic, Rhvolitic, and Silicified 

tuffs). 
Typha angustijolia, 32. 



191 



u. 



Unoonforinitios, 36, 44, 4(i, 02, 67, 140, 148, Ui'.i. 

Underground gases, 67. 

Undergroiind temperature, 66-67. 

Underground water, ()6, 67-70. 

Unio inicklandiru.'). 46. 

Union Claim, Waihi, 10. 

Union (iold-mininsi Companv 143. 

Union Hill, Waihi, 10. :5!», m, 124, 126, IftS. 

Union lode, Waihi, 11, 120, 1:52, 158, loO-lOO. 

Union mill, Waihi, 144. 

Union-Silverton Hill, Waihi, 10, .39, 174, 177. 

Union-Silverton section. Waihi Mine, 126, 128. 129. 

132, 142, 143, 144, l.")S-160, 172. 
Union vanners, 23, 144. 
Union-Waihi Gold-mining Companv, 10, 11, 25, 

14.3, 158. 



Vadose waters, .53. 

Valencianite, 42, 54, 57, 70. 124, 13.5, 158. 

Valencianite, analysis of, 54. 

Vanners, 144. 

Vein.s, mineral, 3, 7 et fieq.. 37. 3S. 43. (4. 46, 52- 

70, 72 el seq. 
Vendor Chvim, Waitekauri, 1 12. 
Ventilation of mines, 18. 
Venus Claim, Xeavesville, 84. 
Vertus Claim, Owharoa. 117. 
Vezin samplers, 21. 
Victoria lode. Waihi, 129, 146, 1.50. 
Victoria mill, Waihi, 144. 
Vitejr luren-s. 2. 
Volcanic rocks of First Period. &e. {nee. First 

Period, &c.). 
Volunteer Claim, .Maratoto, 103, 104. 
Volunteer Creek, Maratoto, 104. 
Vug.s, 1.39, 148. (.SVf rt/.<o Caves.) 



W. 
Wad. .VI. 
Wages. 26. 

Waiharakeke Uiver, 98. 
Waihi, 9-12, 17, 18-24, 25. 26, .30, 41-12, 44. 48. 

51, .53-00. 62-70. 100, 121, 132-172, 173, 181. 
Waihi Basin, 48. 
Waihi Beach, 3. 9, 29. 30, 51. 52, 53, 54, 59. 60. 62, 

121-122, 125. 134. 175. 
Waihi Beach Claim. 121, 122. 
Waihi Beach (lolil-mining Companv (Limited), 

Auckland, 122. 
Waihi Borough. 2. 
Waihi Claim, 128. 130. 132. 1.50, 169. 171. 175. 177. 

180. 
Waihi Consolidated Claim. 12, 132. 
Waihi Consr)lidated shaft, 127. 
Waihi Consols Claim, 1 1. 
Waihi Consols (Jold-mining Conijianv. Auckland. 

168. 
Waihi Extended Claim, 123, 130, 169-170, 171, 177. 
Waihi E.xtended Cold-mining Companv (Limited), 

11. 12, 68, 164, 16.5. 
Waihi Extended .Mine, 66, 69, 130, 1.39, 169. 
Waihi-Cdadstone Claim, 128, 129. 172. 
Waihi Goldfield. 3, 49, 63, 105, 115, 122, 1.32-172. 

174, 177. 
Waihi Gold-mining Companv (Limited). London, 

10, 11, 12, 18-21, 25, 26, 68, 69, 143, 158, 162, 

164, 168, 171, 172, 177, 178. 
Waihi (irand .Function fJold Companv (Limited), 

London, 11, 12, 16, 18-21. 2.5. 26. 161. 162. 168. 

178. 
Waihi <!rand .Function mill, 21-22, 162. 



Waihi Grand .Junction Mine, 18-21, 42, 4.5, 51, .59. 
66. 67, 68. 69. 123, 125, 126, 128, 129, 1.30, 132. 
133, 135, 136, 1.39, 141, 142. 146. 1.50. 1.56, 161- 
169, 170. 171. 178. 179. 180. 
Waihi mill. Waihi. 22-23, 144, 145. 
Waihi Mine, 18-20. 42. 48. 51. 55. .59, 66, 67, 68, 
69, 123, 125. 127, 128, 129, 131, 133, 134, 135, 
137, 140, 141, 142, 143-161, 162, 178, 179. 
Waihi Mine, Martha section, 16, 58, 132, 164, 145- 

157. 
Waihi Mine, Union-Silverton section, 126, 128. 129. 

1.32. 142, 143, 144, 1.58-160, 172. 
Waihi Monument Claim, 62, 178. 
Waihi North Survey District, 1. 46. 
Waihi-Paeroa (iold-extraction Cf)mpanv (Limited), 

12, 143. 
Waihi Plain, 1, 29. .32. 44, 48, 49. 123, 125, 126. 
Waihi Prince Claim. 171. 
Waihi Prince Extended Claim, 171. 
Waihi Princess Claim, 171. 

Waihi Keefs Consolidated Claim. 69. 123, 169. 177. 
Waihi Keefs Consolidated Gold-mining Com])any, 

Auckland, 12, 68, 171. 174. 
Waihi Romulus Claims. 171-172. 
Waihi Konuilus (iold-mining Companv, London, 

171. 
Waihi-Silverton (!old-mining Com|)anv (Limited). 

Glasgow, 10, 25, 143. 
Waihi South borehole, 126. 
Waihi South Claim. II, 108. 

Waihi South Gold-mining ('(mijtany. Auckland, 168. 
Waih Stream, 121. 
Waihou Piver, 32. 
Waihui Claim. Ohui, 89. 
Waikato Coallield, 123. 
Waikato River, 145. 
Waikino. 2, 12, 114, 123, 144. 
Waimangu Claim, Wharokawa, 16, 92, 93, 94. 
Waipaheke Creek, Maratoto, 30, 100, 104. 
Waitekauri, 8, 9, 10. 25, 39, 44, 52, 59, 60, 61, 64, 

105, 108-116, 173, 174, 176. 
Waitekauri Claim (old), ()9. 108, 113-114, 115. 
Waitekatiri Company, 8. 13. 
Waitekauri Cr(m.s Gold-mining Company, 25. 
Waitekauri Extended Claim, 104-105. " 
Waitekauri Extended Gold-mining Companv (Li- 
mited). London. 13, 14, 25, 104. 1(>9. 
Waitekauri Gold-mining Company ('/Auckland), 

109. 
Waitekauri Gold-mining Company (Limited), Lcm- 
don, 9. 13, 17, 2.5, 26. 104. 108. 109, III. 113. 
115. 176. 
Waitekauri-.Tubilee reef, 52. I 15. 
Waitekauri, Lower, 177. 
Waitekauri .Mine, 8, 9. 1 13. 
Waitekauri reef, 115, 177. 
Waitekauri River and N'alley, 9, 29, 39. 44. 108, 

111, 112. 116, 177. 
Waitekaiiri-Union (Jold-mining Company, 25. 
Waitekauri, Uf)per, 105. 176. 
Waiwawa River. 2. 70. 
Walker's tJigantic Claim, Waihi, 12. 
Walker's Maratoto Claim, Maratoto, lOO-lOl. 
Washoe, U.S.A., 3. 
Washoe process, 1 1 . 
Water in mines {see. Pumping, Underground water). 

18, 60, 67-70. 
Waterfalls, 31, 32. 

Water-power, 9, 74, 91, 9.5, 106. 116. 14.5, 176. 
Wauchope, .1. A., 5. 
Weathering of rocks, 40, 47. 
Welcome .Jack battery, (iumtown, 72. 
Welcome Jack Claim, Gumtown, 16, 72, 74. 
Welcome .Jack t!old-mining Company, Auckland, 

74. 
Welcome Jack reef, Maratoto, 117. 



192 



Welcome lode, Waihi, 128, 129, 130, 141, 140, mo, 

153, ir).5, 157, 162, 168, 178. 
Welcome reef, Waitekauri, 1 1 7. 
Wellington reef, Tainia Broken Hills. 78. 
Went worth Claim, Whangamata, 15. 05. 
Went worth Stream, Whangamata, 95, 96, 174. 
Western reef. Tairna Broken Hills. 78, 79, 80. 
We Three Claim, Omalui, 99. 
Whakamoehau {trig, station), 9. 
Whangamata, 3, 15. 16, 44. .59. 61. 9.5-97. 173. 

174. 
Whangamata Gold Corporation (Limited), 25. 
Whangamata Harbour, 31, 95. 
Whangamata Proprietary (Limited), London. 16. 

92, 93. 
Whangamata River, 44, 52, 95. 
Whangaroa Subdivision, 30. 
Wharekawa, 15, 16, 29, 52, 59, 61, 173. 175. 
Wharekawa beach, 50. 
Wharekawa Harbour. .30, 92. 
Wharekawa River and Valley, 1, 15, 16, 28, 29, 30, 

44, 49. 50, 88, 92, 93, 95, 174. 
Wharekirauponga, 59, 61, 63, 97-98, 173, 175. 
Wharekirauponga River, 50, 95. 
Whenuakite River, 2. 28, 29. 
Whiritoa, 45. 
Whiritoa beach, 50. 
Whitehorn, H. S., 4. 

White iron -pyrites, 59. (See also Marcasite.) 
Whitianga Estuary, I, 50, 76. 
Whitianga Harbour, 31. 
Whitianga Survey District. 1, 46. 
Whitianga watershed. 47. 



Wilflev tables, 21, 23, 144. 162. 

Williams, R. E., 180. 

Wilson, G., 5. 

Wilsonite, 48, 125, 128, 181. 

Winding, and winding machinery, 19. 

162, 171. 
Wires, the, 30, 32, 88. 
Withers, E., 15, 92. 
Wood, carbonized, 86, 116. 
Wood, pvritized. 116. 
Wood, silicified, 116. 
Worth, R., 12. 



Xenocrysts, 48. 



Young New Zealand Claim, 9, 116. 
Young New Zealand Company, 116. 



z. 

Zinc in concentrates, 180. 
Zinc-blende, 56, 59, 63, 134, 136. 
Zircon, 41, 47, 56, 114, 115. 



144. 158. 



By .\uthority : John Mackay. Government Printer, Wellington — 1912. 



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